When I was fifteen, I'm pretty sure my main accomplishment was hitting level 40 in Halo 2 matchmaking.
You will probably get lots of valid and actionable advice about branching out to new platforms, focusing on one or two apps, or trying something new -- but more than anything else, keep building things! You've clearly got a ridiculously high level of aptitude and passion.
I don't regret nothing, but I'd sure love being able to write code at that age - If that would make me a better programmer today, which means that I would have to continue writing code for another 17 years :-)
Congrats to the kid.