Dedication is key to everything. I was the fat kid for all my life until I was 17 and lost weight due to an illness. I decided I didnt want to be fat again...and I didnt want to be skinny so I started hit the weights when I was 19 and I havent looked back. Maturity helps dedication, once you realise you gotta work for everything (money, fitness, chicks..etc)..you gotta put in alot to get out alot of it. I think at an older age your mentally in a better place to accomplish anything you want.