I am 15 also! I don't know C, but I know VB.net, Linux, HTML, Flash, Java, and a bunch of other stuff.
I just started my second company that will be lanuching at the end of this month... JanusHosting.Com.
I started a web site design company a year ago and now I am getting in to Hosting.
Goodluck on finding work at 15...I have been laughted at many times by people, but my success makes them look stupid, so hang in there! Also, when you get 16 you can get a job at a web site design company in your area (I have got some offers).