I’ve written before about how the age gap between my oldest two sons, ages 17 and 14, and my youngest one, age 8, affects my life. It’s an odd feeling sometimes to start all over with the youngest one and go through experiences with him just like we did with the first two. As Yogi Beara once said, “It’s like déjà vu all over again.” My oldest son, Billy, recently earned his Eagle Scout rank and my middle son, David is close to it, while my husband and I are just starting that same long journey with Jason, our 8-year-old.

The age gap also means that I’m considered an older mom with Jason, while I wasn’t in that category with the first two. A mid-life mom, as they call it. Kids who are born a while after their siblings are often called “caboose babies.” The last one, bringing up the rear, giving the illusion of straggling behind. This analogy is a sad one to me, as if the caboose is an afterthought, trying to keep up with the rest of the train.

Jason was no afterthought; he was what I knew was needed to complete our family, and though he sometimes tries my patience, he has been a delight to have for a son. I, too, was a caboose baby, since my brother and sisters are eight to 13 years older than me. My mother was 38 when she had me, but I was the only child actually planned, or at least that’s what she tells me. “I knew I wanted another baby,” my mother told me, and so they decided to have one more. I was born on Mother’s Day, which I have to say was incredibly good timing on my part. But I was the youngest, the “baby” of the family, and perhaps that’s why I wanted a caboose baby of my own. One to hold, to savor, knowing it’s your last.

And knowing from personal experience that yes, time really does go by quickly and he’ll be grown in no time.

This was very clear to me recently as I’ve accompanied Billy, a high school senior, on several college visits. Walking behind Billy in a tour group at Wake Forest University was a surreal experience. For a while I fooled myself into thinking we were touring the campus just like we would tour sites we’d visited in the past. But along the pathway, Billy got ahead of me and my eyes fixed on him, and it became real to me that this tour was no ordinary tour of an ordinary place: It was my son’s tour of which places he wanted to live during the next part of his life.

I watched my 6-foot 5-inch son as he lumbered down the steps to the library and remembered the day we got his first library card when he was 5. I watched him and imagined him walking across the campus each morning, hurrying to class, while his brothers, his dad and I would wake up in a different place. How I wouldn’t see him in the kitchen every morning before he headed out to school.

So sometimes it’s a relief to know the other two are still at home, that Jason will be there for a rather long time, providing my husband and me with more baseball games to cheer at, more school performances to watch, more Scout ceremonies to attend.

Of course, the boys are at different places along the road to maturity, so the body changes can sometimes be a source of insight. A few years ago, Billy — who was 15 — was lying on the couch asleep, his arm stretched out over his head. Jason, 6, surveyed his brother’s exposed underarm hair and screwed up his face in disgust. I grinned and explained, “That’s what happens when you get older.”

He pursed his lips for a second and then showed disgust again. “The thought of that happening to me sickens me,” he said.

Jason likes to still do things with his brothers, but as Billy and David get older, the age gap is more pronounced. Going trick or treating on Halloween or to the state fair aren’t family events like they used to be when the older boys were younger; now I take Jason and maybe one of his friends. As this trend continues, I’ll miss having my boys together, and I know, as one caboose baby to another, that Jason will miss it too.