The main challenge I faced is becoming confident enough in my ablities to take on clients. It took months and months of practice, and taking on lots free work, but it's paying off now.
I'm do freelance work out of choice, mainly because coding is something I'm passionate about -- So I may as well capitalise on it.
Main advantage of doing freelance work, is that I can take on work when I choose. Which allows me to do usual "teenage stuff", and still make money -- Whereas my friends work in retail stores, the hours they work often disrupt plans.
I intend on doing this as a temporary thing, but one of my goals in life is to develop websites almost full-time, and make a comfortable living off them.
I owe it all to TalkFreelance though. Before I came to this forum, I knew next to nothing about web development. It has actually changed my life -- For the better and for the worse in some cases.