postcard-from-l-a: At 13, he’s an expert on the infield fly rule but still trying to figure out seventh-grade girls

The little guy turned 13 the other day, as if to rub in all our faces how fast time flies and that childhood can blow by like a Ferrari on the freeway. 13. A teenager.

I’ve been watching him and his classmates lately — at school events, at baseball. They overreact to a lot of things, then are frightfully cool about others.

For instance, a bee will pass and he’ll go freaky crazy. Then a teammate will do something to provoke him — hide his glove, spit in his cap — and the little guy will go deadpan and unperturbed.

At 13, such skits are just beginning. At 13, boyhood is yesterday’s breakfast.

Thirteen years, can you believe it? I remember it well. I’d just returned from my morning jog, and my wife, Posh, exploded onto the front porch, holding little strips of what looked like candy paper. Breakfast?

“Pregnancy tests,” she explained.

“Take them again,” I said. “It’s just like the SATs — you always do better the second time.”

When her scores didn’t improve, we gathered the other kids in the den to announce a new team member. By then, the kids were 19, 17 and 11, so the roster was pretty set. Till then, we’d thought the 11-year-old was our bonus baby. Turns out we’d won the double-bonus.

“Dad, you’re so serious,” the 17-year-old said as the family meeting began. “Are you and Mom getting divorced?”

I said: “No, son. It’s much worse than that....”

At the news, all three of them fell off the couch, physically ill. “Ewwww, you two had S-E-X!” one said, spelling the word the way Grandma did.

“We didn’t know you two were, you know, even doing it anymore!” the lovely and patient older daughter noted. Ewwwwwwwwwwwwwwww.

As their mother experienced morning sickness, so did they — even the teenage boy. Even me.

Then in nine months, there were four of them. The ranks of the enemy had risen significantly, and the kids had a statistical 2-1 advantage.

But a good number, four. Four is the number of Beatles, the number of Noble Truths. For us, four was the number of children we had.

If two is the ideal number of kids, four is a Festivus of new shoes, registration fees, missing soccer socks, car pools, broken washing machines, $300 grocery bills and college tuitions we may never recover from.

Can’t say enough good things about four.

His much older siblings didn’t stay around forever, so after a while the little guy became an only child, raised by a man who still hummed B.J. Thomas songs and insisted TV was better when there were only four channels.

By age 4, the little guy knew the infield fly rule. By 8, I’d taught him how to honk “Take Me Out to the Ballgame” with his armpit.

So things pretty much worked out.

“Dad, I’m practicing my sarcasm,” the little guy told me the other day.

“Like that’ll ever help,” I said.

“You look really good today, Dad,” he said.

“Keep practicing.”

On Thursday, he was getting ready for a school dance. His mother, who in her spare time likes to tinker with old cars, was out back modifying another big-block Chevy. So the little guy turned to me for fashion advice.

“This shirt? Or this shirt?” he said, holding up the choices for the dance.

Watching him dress is like watching Picasso paint ... messy and angular. Each morning, he wakes up 4 inches taller. He has his mother’s chin and his grandpa’s natural slouch. He’s got my sarcasm, evidently the only gene of mine that transferred.

“You’ll look great in either,” I told him.

“You’re being sarcastic, right?”

Not this time.

He’s 13, and he’s still great company and a blast to be around. I like that he talks to me. I like that he asks my opinion, even when he goes and does the opposite. I want to be his buddy, but more than that I want to be his dad.

Friends come and go; you get just one old man — steady, sturdy and immune from silly trends and the stink of what other people think.

Finally, he left for the dance just as you’d hope a kid his age would — a little nervous, a little freaked by the bees that buzz around seventh-grade girls.

He left the house not a boy. Hardly a man. At 13, maybe a better mix of both.

chris.erskine@latimes.com

Twitter: @erskinetimes

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