PLEASE help! VERY important dietry Q!!!!?

Ohmygod I am scared I read this and My name is Angela I am 12 I am thin and I have a tummy too I am 5'3/ 5'4 but I'm not sure what jean size I wear but I have these pants from Abercrombie that are 2 but I'm not sure if that's what I am in other stuff probably not cause I have large hips too. I eat mcflurry's once and a while and other junk food too. I play volleyball!! I am also starting gymnastics and I have a swimming pool and trampoline so it does look like I am a little more active but that's nothing you can't help. You could sign up for other sports you like just for fun like I am doing gymnastics I hope to go onto competition eventually but for now I just want to have fun. I answered this question because we are so alike I was kinda scared.