Four-year-old Oliver has an unusual new interest — one I did not predict . . . and don’t quite know what to do with.

Skeletons.

This is the kid that, apropos of nothing, will try to catch my eye in the minivan mirror with questions like, “Mommy, how did I get here?”

Get . . . here?

“Yes. Here on Earth. On our planet. Where did I come from?”

Ah. Here we go.

I have always been a philosophical mess, so these “big picture” questions don’t really surprise me. In elementary school, I can remember turning to my little sister and asking something like, “Isn’t it weird how we’re humans?” 

But I haven’t been ready for all the questions we’re suddenly getting — especially since I don’t often know the answers, either. (That’s where Alexa comes in. Or Wikipedia. Or, you know, books.)

Many of the recent inquiries have been about bodies. Nothing too awkward, thankfully, but we’ve definitely entered the age of awareness. Ollie thought skeletons were just spooky figures in “Scooby Doo” — Halloween props, or creepy artwork. I nearly blew his mind when I told him that everyone has a skeleton. 

“Where?” he asked.

Under our skin, I said. Bones make up our bodies, and that’s our skeleton.

“But why do I have a body?”

See? So my kid.

I recently pulled up a diagram to highlight the basics of the skeletal system. I didn’t know what most of those bones were called — except for the phalanges, that is. (Every middle-schooler goes through an absolutely hilarious “Hey, Linda, I can see your phalanges!” phase, right?)

He studied it with me, pointing out familiar parts like the feet and hands. We found a kids’ YouTube video that walked us through the topic, too.

Spence and I have been doing our best to answer Ollie’s increasingly deep questions without stressing the kid out. He has a sensitive heart — and an inquisitive mind. I love his curiosity, but I’m also having a tough time coming up with matter-of-fact responses to some of his bigger questions.

And a few have broken my heart a little.

“Mommy,” he whispered one night, when we have our most heartfelt conversations. Ollie shot straight up in bed like a wild thought had just occurred to him. And, you know, maybe it had. “I’m going to keep getting bigger and bigger and bigger?”

Well, yes, bud, I whispered back. I certainly hope so.

This was brought on by needing to retire his John Deere T-shirt — a longtime favorite. It’s a 4T, and the kid has moved several sizes beyond . . . plus it’s so thin from constant wash and wear that it’s fraying at the edges. Small holes dot the neckline.

I’d tried to tuck it away without him noticing, feeling sad myself. It was his go-to outfit for more than a year. You know those “I Really Love My . . .” features in People, with a celebrity wearing the same scarf or hat or boots in a million settings? That’s Ollie’s John Deere shirt. So many of my favorite pictures include him wearing it.

I’d been quietly pulling a few worn tops from his bin to add to the closet collection. Oliver saw me packing it up because, of course, he misses nothing — and he was despondent. I wound up putting it back, though it’s since been gently stored.

“I’m going to get big like Uncle Eric?” Ollie continued, thinking of his six-foot-tall buddy.

Maybe. You’ll get taller, though we don’t know how tall. We’ll see when you’re a grown-up.

“But I don’t want to get bigger,” he suddenly wailed, and the way his tears came on really took me aback. “I want to stay little.”

Ugh. Gutted, I tell you.

I wish I could say I had an eloquent response — something that soothed my son, profound and memorable. I didn’t. I struggle, too. Though I do feel decidedly “mom-ish” these days, my adult skin — and parent skin — didn’t quite seem to fit for a long, long stretch. I always wonder if I’m doing this right. “This” being, you know . . . everything.

I do feel a lightening lately, though . . . like my eyes are readjusting after exiting the cave of maternal exhaustion, anxiety, worry. I find joy in little moments. I’m not so tense. I trust my instincts more. I’m less easily phased by spilled milk or thrown toys. I have my moments, don’t get me wrong — but I also feel like maybe I’m doing OK.

And I hope that, in time, I’ll be able to cobble together responses to the many big questions my children will ask of me.

I might not have “answers,” but I hope I’ll have honest and thoughtful words to share.

And when in doubt? Well, I’ll look for the diagram.