Symmetry
Man I think you've got so much great potential.
Even if you didn't change anything and didn't 'grow' you are a fine example of symmetry (and I understand about your legs, and you can keep workin 'em).
Thing is. Listen to the guys and don't over work (i.e., add mass out of proportion). Hard to do. But as it was said earlier, your great narrow waist is a hard thing to keep --- ! and if I were you, and your age, I would to everything to keep this! That is, unless you want to go pro in the BB world....then you'll go for the MASS...etc.
I also would like to comment, unless you are 'on stage' I see NO PROBLEM at all with the nip piercing as, it can be a very sexual thing as you stated.
Adam
West L. A.
PS: keep it up, be as consistent as you can, don't eat crap, and man, you are doing FINE!