How can i look pretty with a kinda chubby belly?

I'm 12 and i want to look good next year. Im kinda chubby and i want to get rid of that fat. but for now i wanna look good. I always straighten my brown hair that is right above my shoulders (should i grow my hair out?) i like clothes from places like aeropostale and abercrombie, but most of their shirts are rlly tight which i look fat in. And next year when i can wear a little makeup, i want to wear some mascara and lip gloss(do u think this is good?) Im kinda short with brown hair and brown eyes and i wanna look good in cute clothes from the places above. For exercise, idk wut to do. when it gets warmer, i was thinkin bout walkin or joggin. i do dance once a week for an hour which can be a good work out. I need some ideas for how to exercise (but not too much sports cuz im bad at sports), wut i should wear, wut to eat, how to wear my hair, makeup next year, and any other ideas that can make me look better. Please give me so tips, i really need it. Thank you!