Gained a bit of weight?!

Not a lot just a average flab. I used to have a high metabolism though it runs in my family to have a high metabolism when your younger and lose it when your older. I'm 12, my friends all have flat stomachs i want that too, i hope i'm not being too greedy. Most of my clothes are from Aeropostale and i don't want to wear them because there tight fitted, not like baggy t-shirts. Recently i have been wearing jackets to cover up my stomach. Any ideas for a girl on a tight schedule? I lose fat quickly though i gain it back when i eat fatty food too XD I drink a lot of cold water to maintain my face( i get acne easily, also i heard drinking cold water increases your metabolism) I try to get as much sleep as i can though i study 110% because my parents don't have enough money for college so they want me to get a scholarship, i've won a few sciences fairs and already have a bit over $2,000 in scholarship money. I don't eat sweets( baked goods and candy) , i've always hated them, i don't drink soda either, it upsets my stomach. I like chips and ice cream though lol.


So i need something that wont take longer than about an hour and healthy ideas for lunch and breakfast? My parents wont let me choose my dinner lol.