How do i get a flat belly for summer?

I am 14 and im going on a bunch of summer vacations and i am 5' 2 and 117 but i am not fat i am built but i do have a little belly or gut. i need to get rid of it for summer...i am in athletics and run a mile a day but i am a big eater...but i don't eat sweets..but i need to lose weight FAST!!