What they picture is the weekend. Going out every Saturday night, clubs, drinking, the version of sixteen everyone seems to agree on, where nothing counts yet and that's the point. I've never wanted it. I like being with my friends, and I don't like clubs or going out to drink. I like spending time with them, and that's it. If that's the adolescence I'm supposed to be missing, I'm not missing much.

What I'm giving up is quieter. My classmates share a life outside school, time they spend together that turns into something between them, and I mostly wasn't there for it. When they talk about it, I feel a small sense of not measuring up, and at the same moment an odd kind of pride.

Their free time is something they spend together. Mine is something I fit in, between school, training and whatever I'm building that week. I've spent years getting very good at fitting things in, and not much time fitting in.

For years it wasn't even a choice. I lived far from everyone, I had no scooter, and there wasn't really a group to go out with, so I wasn't choosing work over friends. I had empty time, and building filled it. The projects came after the loneliness. In them everything depended on me. I could watch an idea turn into something that worked, and see, week after week, that I was getting better at it.

Then, this summer, the excuse disappeared. I got a scooter, and with it a group of friends I go out with. I'd be with them, having a good time, and a new idea would arrive in the middle of a conversation. Or I'd catch myself waiting to go home, at an age when everyone else is trying to get out of the house. Building started as a refuge, and I'd still go back to it with the door wide open.

Going back to it lights me up more than it calms me: I've had an idea and I have to try it now. It also makes me feel even, the way you're even with someone once you've settled a debt. An afternoon I don't use feels like time I owe. My friends are fun, but they don't make me even.

I've tried to work out who I owe it to. Myself and who I could become, the kid I used to be, my parents, who chose safety, the world I keep saying I want to contribute to: all of them, probably. But when I imagine stopping, living like everyone else for a year, no disappointed face comes to mind. I see a void, and whatever I owe, I owe it to that.

I think I first sensed it as a kid, without a name for it. I used to ask how far humanity would go, over and over, the way you might stare at the sea without any idea how to answer. Much later I noticed what kind of question it was: one you ask from the stands, watching the game and wondering how it ends. Reading about people who had built things from nothing turned it into another question: what can I do to help it go further? You can't ask that one from the stands. You have to come down.

That void is the only thing I'm afraid of. I'm not afraid of failing or of starting over, or even of dying. I'm afraid of leaving without having left anything, of getting to the end and finding out I only ever watched.

The fear stays in the background, though. On the nights I leave my friends early, what pulls me home is the idea waiting for me.

So, to the people who say it kindly: you're half right. I am giving up some evenings, and some of what my classmates share without me. I know what that costs, and I'd still choose what's waiting for me at home.