Nothing surprises me more than the advancing ages of our sons. Your own age is a given, and somehow you get used to it, and in my case at least, tend to anticipate the next annual changeover. I think of myself now as 88, although that won’t officially happen for another six months. But the surprise to me is that our eldest of three sons made 63 last year and the youngest just turned 59. In between is a 61-year-old.

Admittedly these ages are “just numbers,” as the somewhat pollyanna-ish saying goes, suggesting that age — especially old age — doesn’t make a difference. But of course it does.

Birthdays ask us to pay attention. For me, this season of flowering trees brings back strongly the day of our third and youngest son’s birth. It was a brilliant blue day and although my contractions had begun, I was now an experienced birth-giver and knew not to show up at the hospital until they were coming more frequently.

The first time around, some five years earlier, ignorant of this advice and many other things, we had arrived at the hospital in the early morning, at the first sign of serious contractions. David was born around midnight, more than 12 weary and hungry hours later, and only after I had walked many miles up and down the corridors.

Our middle son Mike was born much more efficiently on a snowy day in January. In anticipation of a serious storm, we had engaged our first snow plower to clear the driveway, just in case. The snow held off long enough to get us unproblematically to the hospital, and Bill went home after Mike was born.

That was how things were done then: Husbands did not take part in births. They could sit and smoke — yes! — or read or snooze in the waiting room, but they did not participate in the great event or stick around afterward.

The next morning Bill found that our car, which was sitting in the driveway, had quietly developed a flat tire. Well timed.

The third time around, to make things go faster as we waited for the arrival of our son Will, we went and sat under the brilliantly blooming apples trees in a friend’s sloping backyard.

I was given a comfortable wicker rocking chair to sit in, which almost immediately fell over backward on the incline. Much consternation but no harm done, not even the speeding up of contractions.

Those were birthdays. Although it seemed to go without saying that we wanted to have children, we had certainly done no planning. Still, we ended up with highly symmetrical spacing. Two and a half years between each of them, just enough time for me to toilet train the older one before the next one was born.

There was, it’s true, a certain amount of just sitting and reading to them while they sat on the pot, waiting for action. As I remember, “Mike Mulligan and His Steamshovel” was just about the right length. Worked pretty much like a charm.

That was then. In some ways it seems like only yesterday and in others, of course, eons ago. It’s the odd thing about time, as many writers remind us, that it contracts and expands. If I look ahead, I do not see eons, but only a series of tomorrows. A couple of years ago when we put a new roof on our garage after a huge spruce tree fell on it, the contractor assured me that it would last for 20 years. That put it into a sort of perspective.

“Longer than me,” I said.

Marietta Pritchard lives in Amherst and can be reached at mppritchard@comcast.net.