I think it all depends on the person and their situation. I've been training since I was 10 years old, when my dad finally let me try out some weights. I haven't gone a week with training since. I'm 18 now, and am heading to a very competitive situation in a D-1A school for football. No reason not to juice if you're smart enough not to get caught, and have vast experience. NOT EVERYONE STARTED LIFTING @ AGE 18!