Our son FaceTimed us on Sunday. His timing was awful. We were at an A’s game, about 10 rows up on the 200 level, and the game was tied. “Where are you?” he asked. I turned the phone toward the field. “Oh,” he said.

Even though it was an A’s game and not a Giants game, we could barely hear him. Turns out 20,000 fans can still make a lot of noise. All I caught was something about how a friend he’d met doing a school service project three summers ago in South Dakota had come to tour the campus. She was still in high school. He met her and her family and showed them around. The experience, I gathered in broken phrases, blew his mind.

“I was showing them around and it occurred to me,” he said as Coco Crisp took a 2-1 slider on the inside corner, “that other than you guys, no one else from before this year has been to my school.”

It was true. His school is so far away, and he’s been so occupied by the adjustment of going from “successful, cruising high school student” to “first-year engineering student and radio deejay” that he hasn’t exactly been dishing out invites to all of his friends back home.

“I was wondering what I must seem like,” he continued about his visitor. “I feel like I’m much older than I was the last time I saw her.”

Solid assessment, my wife and I both agreed later, while waiting at Coliseum BART to be whisked from the East Bay back to San Francisco. He is much older. We’ve both noticed it.

I’ll be straight with you here: Our boy has always been a “spirited child,” dating back to the days of his Ikea toddler bed, which the 18-month-old him refused to settle into without a fight. He’s his own kind of social justice warrior and not one to let things die easily. And like most parents, we sent him off to school with a healthy dose of trepidation surrounding what those in the know like to call “life skills.”

“What’s he going to do when he realizes that toothpaste doesn’t magically appear whenever he needs it?” I would ask, just before settling into a nice session of “Why is he always broke? What is he spending all of his money on?” fretting.

And at first, the child we sent away to school remained the child we raised — same issues. But then, sometimes with great subtlety and sometimes like a punch in the face, he began to evolve.

My wife was the first to notice, because that’s just how we’ve always done things around here. She notices the good stuff and relays it to me, at which time I take a break from worrying about the bad stuff and nod in agreement. In December, when he didn’t complain once about having to work and in fact excelled at his job; at spring break, when he was a full contributing member of our Yosemite family vacation team, offering good suggestions and cheerfully accepting defeat if they were not adopted (except for the cross-country skiing day, but I can see that snowboarding would’ve been more fun).

And now, planning for his interim summer term abroad in Germany, saving half of his allowance each week and scraping by on what’s left. The high school version of him would’ve blown through the entire allowance and begged for more, then gotten angry when rebuffed. Color me impressed.

Maybe there really is something to this going away to college thing, and you actually do learn things outside of class as well as in. Now let’s not get crazy here. I’m positive that the tight frame he offers up during FaceTime is to prevent us from seeing the condition of the rest of his dorm room. But baby steps, right?

It’s not like I wasn’t paying attention, but still, this growth spurt of maturity caught me by surprise. It’s been quite a ride, this first year. Having a ringside seat to watch as our little boy slowly pulls on his man pants one leg at a time fills me both with unspeakable pride and such beautiful heartbreak. I can see into the future, and I’m really starting to like how it looks.