How can a teenage girl lose belly fat?

Im 14, and I'm 5'9 and pretty slim and muscular all around, except for my stomach. It's flat from the front, but from the side there's a tiny bump and I hate it!! I really just want to get rid of it fast! I have thought about working out more, but is there any specific excercises I can do to tone it up/flatten it out and possibly get some abs going??