I need some help with my health issues.?

Okay I'm 13 years old. I'm a girl lol. I'm 5'3 and weigh around 120. Well I'm trying to lose some weight. I go to the gym every now and then. But I'd rather just eat better. Well everyday after school i come home and I'm starving. So I get a snack. Well usually it's just a cheese stick, or a apple. Well after that i'm still hungry, so i go over to the pantry and get a ding-dong... or two. Then maybe another cheese stick. Well my point is I cant eat right! And if i do i eat a lot of it!! Please help! I'm tired of looking like i am. I want to be skinny around the summer time.