I’ve been reluctant to say that I recently turned 80. I feel as though I’ve done something wrong, or been careless, though it isn’t really my fault.

Eighty isn’t as bad as I feared, to tell the truth. This Island is well supplied with 80-year-olds who still swim, sail boats, build houses, and write poems and books. As a writer myself, I fit right in. Shake a tree on Martha’s Vineyard and a novelist falls out.

I swim, too, at Eastville Beach, one my favorite spots on the Island, though “swim” might be a misnomer. With my messed-up shoulder, a dog paddle is the best I can do. On a sunny summer afternoon, Eastville Beach is true cross-section of Island life — splashing kids, couples basking in their beach chairs, sea glass hunters, fishermen, families and groups of friends settled in with their coolers and umbrellas.

To the regular swimmers, the place is known as the Riviera, and we keep swimming after the summer ends and the water temperature drops below sixty. Salt water is healing, and cold salt water gives the endorphins a polar jolt. In November, the Riviera is my frigid Fountain of Youth.

Now that I’m 80, I understand the importance of the daily walk to the post office. I walk in the spirit of Kurt Vonnegut, who regarded the trip to the P.O. as a valuable human ritual, a chance to get out, move around, get a glimpse of the ongoing life all round you. My route takes me past Chicken Alley, the gritty thrift store that’s just waiting to be turned into a TV show. The daily local stories touch the universal themes: joys, fears, losses, ordinary human struggles.

My companion and wingman on these walks is a terrier named Cyrus, who greets everyone we encounter, both two-legged and four-legged. He packs a lot into a short meeting and then he’s ready to move along and continue his important investigations.

But he’s not rushed, and neither am I. You know the one about the farmer who takes his pig into the apple orchard, holding him upright so that he can eat the low-hanging fruit? His neighbor observes this and asks what he’s doing.

“Feeding my pig,” says the farmer.

“Doesn’t it take a long time to feed him that way?” the neighbor asks.

“Maybe, but what’s time to a pig?” the farmer replies.

Cyrus and I frequent the dog park and the beaches where dogs are welcome. After two years, we’re part of the local dog network. While we were walking along Beach Road, a woman in a truck slowed down and shouted at me: “Kona’s missing! Keep your eyes open!”

I recognized the woman but didn’t know her name. Kona — well, I know her name and the flop-eared sire of her pups. She was found safely, by the way.

For most of my life, I wore a shirt and tie to work. Now that I’m eighty, I dress for the dog park. My usual outfit is sweat pants and a Cottle’s hoodie. I have two of them, in fact, one a Carolina blue and the other a Harvard crimson. One day my son phoned from Whitefish, Mont., to tell me that he was looking at someone in a Cottle’s hoodie — the blue one.

To be clear, I do have some standards. If you see me at Stop & Shop in pajamas amd mismatched socks, please call my wife and tell her where I am. She’s lovely and kind and works at the hospital. I’m a house husband, sort of. When she comes home after work, she asks for the news, hoping I’ll have something to report, but I usually disappoint her.

Of course, I do vary my routine every now and then: I volunteer at a few places, meet friends for lunch, go to lectures, take classes. Every day at the writing desk, I try to make myself laugh and I’m always glad when I have a funny line to try out on her. Mostly, I’m glad to hear her news.

I’m not sure I could have lived such a peaceful life before turning eighty. I was too driven, and — I have to admit it — I’m still ambitious in certain ways. The book I’m working on is a mountain I’m determined to climb. I actually have goals for my swimming, and I’d like to shoot my age on the golf course. I am still trying to live up to the ideals of conscience and compassion that were imprinted on me in high school.

I read newspapers and books and try to understand something about our violent, heart-breaking world. And yes, sometimes despair grows in me, as Wendell Berry wrote, and I fear what my life and my children’s lives may be.

Still, I am mostly content, and more at peace than when I was 40 or 50 or 60. Back then, I thought about growing old in terms of the TR — the Time Remaining. Now, at 80, there’s much less of it, but here’s the paradox — it doesn’t feel that way. Somehow I’ve come to think in terms of days, not years, and to take the days as they come. Each one seems to contain realms of time, as much time as I could want or use.

Like many my age, I wake early, usually while it’s still dark. From the bedroom window, there’s a view over the lagoon, and many mornings I watch the sun rise. Especially in winter, daybreak is extravagant, a radiance of pink and peach and gold, the gaudy colors rising behind the dark silhouettes of the trees and over the still water.

I think then of the final lines of that Berry poem: “And I feel above me the day-blind stars Waiting with their light. For a time I rest in the grace of the world, and am free.”

Stephen Goodwin lives in Vineyard Haven.