I'm 14 years old and I'm a 32 H... I get made fun of everyday because of it,and I hate them, I want them to be at the most Cs... Its very hard to do the stuff I love to do like cheerleading,dance,running with my friends... my bra leaves marks on my shoulders and I just want them to get smaller... anything you say will be helpful thanks :)

If you are overweight, loose weight and it will disporportionally come more from there because it's a huge body fat mass behind the very small mamary glands.

I don't think that alone will come close to what you desire (H to a C), but it's a step in the right direction, when you get a bit older, and you might be a candidate for rduction surgery, which isn't a minor surgery, and thus isn't without risks, so best left for when no other options exist.

I'm actually 120 pounds so I'm not sure it that's it

At 120 lbs you aren't obese no matter how tall you are.
Weight loss is not going to work in your case. Not resulting in more than one or maybe two cup sizes at most I would guess.