advantages: you heal faster, can move and bend better, and can be more impulsive (at least you have a good excuse for bad decisions). disadvantages: less worldly wisdom/experience, often too caught up in oneself to see consequences. Little things seem like bigger deals than they really are.
advantages of being young: you have your whole life ahead of you disadvantages all you want to do is grow up
The advantage is that it seems easier to change and start over after bad decisions. The disadvantage, (for me,) was being overly emotional as a teenager.