I recommend getting a degree of some sort. I started university at the tender age of 22 after piss-farting about for 4 years after school, always with the intention of flying in the back of my mind. So, after 4 years at uni I had a B.Sc(Physics), and six months after that was into the flying full-time at the slightly less than tender age of 26!
Had a ball at uni, learned to live of $150/week and got a good degree too
Got my Multi- IR flight test in a month and haven't looked back.