Re: mole on nipple
I don't think having a mole on your nipple is more likely to be skin cancer than on any other part of your body. And because the nipple area is more pigmented than the surrounding skin, it might not be a mole at all. Have you had a doctor look at it? Because you said you are 16, you are could be having some changes hormonally that could be causing this area to change in pigmentation.
I don't think I would be overly worried about it if I were you. But you should certainly show it to your doctor at some point. It could be any number of benign skin growths and not a mole at all. Or it could, in fact, be a mole and still not be anything to worry about. But until you have a doctor look at it, you may not know for certain what it is.