I'm glad I started when I did (21). It took me this long to gain a good understanding of nutrition, settle into a really good routine, know exactly what I was doing, and to really appreciate my hard earned gains. Because of all this, I think I respect my body and gear alot more as well.
I talk to alot of people that want to jump into things after 3 months. When I first started lifting, I was so sporadic in training, that I wasn't sure this was something I wanted to commit to, and if I was going to start injecting myself with drugs, I better damn well be sure that this was something I was going to commit to.