You cannot spot reduce, you lose body fat, you lose it all over.
How do you know its not muscle and is fat? its an odd place to hold fat, most people tend to hold fat around their torso.
Wait until your a little older as when your hormones kick in (roughly 17-24) your figure will completely change, if you fight against the tide you could cause yourself more problems then you can deal with. So I'd say unless your overweight or obese, leave your body mass alone. At your age you will hold onto some fat, its called "puppy fat" and is known to exist as it holds onto many vitamins and nutrients and also alot of cells which help your immune system. It also holds energy so you can grow. If you mess with this you can cause yourself many problems with your body so unless you really are overweight, I'd say leave it alone! You only get one body, messing it up at such a young age is really not something you want to do.
And just to confirm, if you are overweight and want to lose weight, it comes off everywhere, not just one place, you cannot chose where it comes from, it comes from everywhere. Your better off waiting for your hormones to start first though as your body will need to develop propely to be healthy.
