You could work on things for yourself. As a 16 yr old presumably living with your parents there's no risk. I'd suggest starting with a small mobile iPhone or Android app. Make a little bit of side money while building a portfolio you can use to your advantage later.
How would you go about finding a concept to build a app around? You don't want to end up building a so-called "sitcom" app which no one uses.
When I was closer to that age, there wer 16yo running major pirate software networks, art groups, bulletin boards and even developing related software for the fun of it... if someone finds it useful, awesome, if it solves a problem you experience even better.
It doesn't have to be widely used for the experience to be beneficial, and to make a little money off of it.