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.
Personally when I was your age I was creating websites. I made a book search engine, and a geoip enhanced amazon affiliate ad system for easily adding affiliate ads to blogs and websites. Both achieved some minor success, although they eventually got banned by Amazon (the book search engine because I was scraping Amazon content, and the ad system because it got adopted by a lot of spammy content farmers because it was a highly effective way to monetize Google traffic, so Amazon blocked my API access).
So the ultimate success of my ideas was minimal, but the experience I gained from those two projects got me a great job at a startup that has led me down a very successful career path so far.