Whoa... 15-year old kid starting a start-up? Good luck! I'm 15 too, but even though I've done some some programming in the past three years (compilers/interpreters, PHP, some Java GUI, reverse engineered a file format) I don't think I would try to start a company, school taking up 8 hours a day and all that. Yet.
Better to start now then when you're trying to jugle a startup and a demanding full time job. I work around 9-10 hours a day and still have plenty of time to work on my business. So there's no reason you can't give it a shot! Some great companies have been started in people's spare time. You never know what might happen, even if you start with something small.
In hindsight I wish I had tried to start up a business when I was at school. Even if they had been failures, I'd have a pretty good understanding of certain business aspects that most young people would have yet to have learnt.
I'll second that. It's only when you get older and enter the work force that you realise how much spare time you had when you were in school.
When I was 14/15 I started a business in school via a government funded scheme called "young enterprise" that encouraged youngsters to create companies. We had several business people come in from outside school to give advice (ours were a local HSBC bank manager and someone who worked in advertising from Intel). Myself and my friends ended up building a company that made & sold key rings of all things.
It didn't work out very well but the experience was great - I learned that business is really just about making something that people will buy and selling it to them for more than it cost you to make. When you understand that all of the big words business people throw around are not so intimidating.
I'd encourage any young person who is thinking of starting a company to just go and do it. Whatever it is they end up doing and whether it is a big success or completely tanks doesn't really matter. At a young age you can always recover from failure and the experience you gain will make it all worthwhile.
