I wouldn't put it past gliese1337. I turned 24 yesterday, and I can honestly tell clients that I've been programming professionally for over a decade. (Obviously, my abilities/standards have changed since then, and so have my rates... hopefully that trend will continue!)
I picked up a few jobs online around that same age, 13-15. I don't think I really had enough drive to start picking up better jobs or taking on follow up work for the clients.
Was a better time in a way, not really needing money I was actually more happy just doing my own stuff and helping out with sites online I was interested in.