i'm only 13, well 14 in 7 months, but a kid in my grade (same age as me), started lifting weights, and got pretty big and got skinny.i want to work on my upper body really not much my lower, like my arms,chest,back and shoulders.also my abs.i might be a little younge but i see my friend and what he looks like now....and i want to look better!!!can u tell me how to work on them things? please and thank you!