I work out at the Y five or six times a week, so I see a lot of naked women.

There are very elderly ones who stand crookedly in the shower, bones protruding, washing their thinning, silver hair. Others have bodies so wrinkled, the folds of skin fall like ripples from their shoulders to their thighs. One woman of about 60 has had a double mastectomy; she stands facing out under the hot air dryer on the wall, scars running diagonally, like a geometry problem across her flattened chest.

These women neither frighten nor repel me. But there are many who do.

They’re the middle-aged matrons who wriggle into stretched-out nylon thongs and strut around the locker room with sad, flaccid butt cheeks dribbling out. The ones who climb on the scale and stand for full minutes, inching the weights backward an eighth of a pound at a time, sweat breaking from their clenched foreheads. Those with hard, synthetic breasts and nipples that point ahead like ray guns: strange, white, manmade protrusions on bodies otherwise middle-aged, sun-worn and tan.

“Never let me do that,” I’ll hiss at my daughter as we leave. “If I ever buy a thong, you have to shoot me. Promise.”

She rolls her eyes: an entire revolution, the way only teenagers can. “Don’t worry,” she’ll say. “I will.”

I understand the temptation, or at least, I’m beginning to. At 41, my gray hairs now number at least a dozen and despite the fact that my weight is steady, my body somehow is becoming simultaneously bony and too soft. Running hurts my knees. Caffeine keeps me up at night. When I tell people I have a son who is going away to college next fall, they rarely shout, “You? Impossible. You’re far too young!”

I’m hardly the first to be struck by this sudden sense of age. Yet, I have to admit, cliché though it may be, all these changes come as a rather jolting surprise. And I don’t want to turn out like those sad thong-wearing women with the synthetic boobs and sagging butt cheeks.

So I went in search of wisdom and grace.

Faith Sullivan [4], the novelist, is 74. She’s small and delicately rounded, like a sparrow in winter. Her hair is pewter and pure white, cut in an old-fashioned bob. She wears bright clothes and oversize glasses, like Angela Lansbury in Murder, She Wrote (which remains, in syndication, Sullivan’s favorite TV show), and she calls everyone either “Darlin’” or “Dear Heart,” depending on the level of intimacy.

Among the people I know, she is universally loved.

“Faith has shown me how to be more than just a writer,” Kate DiCamillo, the Newbury award-winning author, told me. “I remember being in a bookstore in Grand Rapids, Michigan, and Faith had been there before me. They had a letter from her on the bulletin board thanking them for the lovely time that she’d had reading. And I remember saying to myself, all the bookstores I visit, they deserve thank you notes, too.”

I’ve seen it myself. Sullivan’s last published work, Gardenias, came out at exactly the same time as my first novel. I spent weeks compulsively checking my book’s Amazon ranking, driving myself and everyone who knew me crazy with tedious fretting about low sales, until a luncheon at which Sullivan told me she didn’t even have an Internet connection and wasn’t at all interested in anonymous reviews.

“I gave a copy to the lady who does my dry cleaning,” Sullivan told me. “And she was just delighted. That’s what you have to do, darlin’. You wrote a wonderful story; now share it with people who will appreciate it.”

This is how she became popular: through word of mouth, bookstore clerks who hand sold her first several novels, local reading groups that bought her book en masse and told all their friends in other states about Sullivan’s work.

“I’ve known Faith for ten years,” says the writer Kit Naylor. “And she goes whenever a book club or a library asks her to speak. It doesn’t matter where they are or how many people attend. And she’s genuinely happy to do it.”

That’s how Sullivan behaved when her first three books were published — a comedy, a mystery, and an experimental novel she describes as “like magical realism” — in the early 1980s. All three are out of print now, but her 1988 semi-autobiographical novel The Cape Ann continues selling today. And she’s written three more books, The Empress of One, What A Woman Must Do, and Gardenias picking up on storylines from Cape Ann.

She’s been married to former Los Angeles Times theater critic Dan Sullivan for 43 years — since shortly after they met during a rehearsal at what was then the brand-new Dudley Riggs Theater — and has three children, ages 42, 40, and 37. They lived on the West Coast for 20 years before returning to Minnesota (“home,” she says) in 1990.

Today, at work on a fifth about Hilly Stillman, a minor character from Cape Ann, Sullivan is writing more slowly than before. Since July, she’s had chronic headaches due to inflammation of the nerves at the base of her neck and has been on a regimen of steroids and heavy-duty painkillers. But when I call her to ask if she’ll have dinner with me, she accepts on the spot and tells me cheerfully she’ll simply “take an extra pill” before our meal.

She wants to go to Three Fish, she says, because she always “feels good” there. So I arrange to meet her on a Wednesday evening at 7. But when I arrive at ten minutes ‘til, she’s already sitting at the bar, holding a martini, laughing at something the bartender just said, and wearing a dark velvety suit that looks like a cross between an Asian pantsuit and very high-class pajamas.

We sit, and before even looking at the menu, I tell her why I’m here. I want to talk about writing, sure, but mostly I want to learn now how to age with her kind of style. She pauses, looking startled for a couple seconds; then something happens and she vaults right over the surprise. Sullivan grins and reaches out to pat my hand.

“Beware, whoever you are, if you try to make me feel out of it,” she says. “I’ve never had a ten-year birthday — not 40 or 50 or 60 or even 70 — that seemed daunting. Each time, I looked at my life and said, ‘OK, this is a lot of fun.’ And I don’t feel any older than I did at 16. I’m still just as naughty as I was then and proud of it. I go to book clubs and there are young women there, 30 years old; I get them and they get me. We’re sisters under the skin.”

It’s true that despite their vintage feel, Sullivan’s novels are read by a wide range of ages. She captures the experience of being nine or 12 or 17 as well as she does the complications of being 32 or 60. Poor, privileged, married, divorced, child of a morbidly depressed mother or mother of an adult son ruined by war. She’s written authentically about all of these conditions and says it’s the perspective she’s gained in 74 years of life that’s allowed her to do so.

“Sometimes age makes you more philosophical, sometimes it makes you angrier and more active.” She pauses and drinks her Tanqueray, sliding the olives off a plastic spear and chewing them one by one. “I think the secret is to stay interested. And interesting. You want to be an old person who’s involved and attracts younger people so you have friends all across the ages.”

Part of it is the life she leads. Sullivan and her husband are activists who moved from South Minneapolis to North in 2003, in part to show other people what a wonderful part of the city it is.

“We live in a very mixed neighborhood — racially, economically, in every way you could imagine — and that’s exactly what I want in my life,” she says. “Too many people as they get older feel less secure and want to be “safe” all the time. Consequently, they’re cut off from the real world.”

But Faith and Dan wouldn’t dream of limiting themselves to some safe, doddering existence. While she teaches and mentors writers through the Loft, and drives herself around the five-state area doing readings and public library events, Dan runs a critics program for the Eugene O’Neill Center in Connecticut and writes frequent political editorials. Both will campaign full-time for the Democratic candidate — whomever that turns out to be — in the next presidential election.

Our waiter arrives at this point, pleasant but clearly distracted. He’s brought me a long-ago ordered glass of wine. When I ask if they can substitute vegetables for the mashed potatoes that usually come with the salmon and he says, “Of course.” Sullivan declines a second martini and orders the grilled prawns.

After he is gone, we resume a desultory conversation, mostly about literature. Her favorite authors, Sullivan tells me after she drains her glass, are William Trevor and P.G. Wodehouse. She’s been reading mysteries, too, and revisiting Jane Austen, whom she loves. When her new book is finished — and it will be a while, she warns, because of these ridiculous headaches — she intends to go back to Milkweed Press “if they’ll have [her].” (They would be crazy not to; Gardenias was one of their top books in 2005.)

“I love Milkweed,” Sullivan says. “Their integrity and the way they treat their writers. I love that they’re local and I feel personally connected to the operation. That would definitely be my first choice.”

Abruptly, I return to the original line of questioning. This time, I describe the scene of the locker room at my Y. And when I’m done, she tips her head thoughtfully.

“I used to be more judgmental than I am now,” she tells me. “In fact, I was a bit of a bitch as a young woman. But I think that was basically being insecure. You knock around and reach a certain age and begin to feel good about yourself and who you are. Then there’s nothing to protect: you’re just you and you open yourself up at that point to the vulnerabilities of everyone around you. And you get to be” — here, she leans forward — “fucking mellow.”

This is exactly when the waiter arrives with our meals and sets down my dinner: bare salmon draped over a heaping mound of mashed potatoes.

I clear my throat, preparing to demand that my meal go back to the kitchen and be made right. But when I look across the table, I see Sullivan pick up her fork, eyes glittering, to dig in. “I just love the food here!” she says.

And I realize that making my stand would demolish our dinner together. Even if they took her meal away and brought her a fresh one timed to match mine, it would diminish her enjoyment. And besides, the man served our plates and left without a word; so, there’s no longer anyone there to whom I can complain.

The potatoes are not only plentiful, they’re way too salty. But the salmon is quite good and underneath, in a snowdrift of spuds, there are a few thin strips of braised spinach. I eat these and for once, I shut up.

This, I’ve decided, may be step number one on my self-improvement plan.