I started athletics when i was 8 years old, currently running for North Devon Athletic Club and compete regionally and nationally. Train 5-6 tomes a week for it. Specialise in steeplechase but not too bad on the sprint side too :P.
I actually started the treadmill at 16 as the instructor guy advised me not to go straight in at say 20. But i just found myself increasing the speed throughout the run until i reached 20, then it wouldn't go any faster :P