Actually that isn't true. He was thirteen the day his brother found the thing that they later discovered was an anti-gravity machine buried in the rubble of a planet-sized trash pile.
Of course that version isn't true either.
The real story is one of a couple of kids on some backwater archaeology dig of a world orbiting some no-name brown dwarf who just got bored one day and decided to see what was over the hill. But that's how things really happen. The stories we read are good, but the real story, ah, that's where we learn the truth about ourselves.
So let's stand with them, under a never-sunny sky, baking in the infra-red of another day in the back-end of nowhere. Two kids ready to go off and play. The ancient whatever-forming machines that gave the world its atmosphere are working well for once, so it's a nice enough day, a day when the world beckons and we must go run and find what it gives us.
They call it Junk Pile. Why it was there, no one knows, but for more than two million years the Mercury-sized ball of rock had been the cross roads of a dozen different star-faring races.
Not all at the same time. Intelligence doesn't last long in this unfriendly universe. Smarts aren't rare. Life is everywhere, nourished by a hundred million stars. And where there's life there's nearly always intelligence. Everywhere is busy, everywhere is bustling. But no one wants to talk, no one wants to see the stars, and it's so much easier to hunker down at home and go matrioshka in the computronium rubble of a solar system. And then it's very easy to die.
[story fragment half-dreamt flying from San Francisco to London]