I am only 13 and 5'3, size 4-6. I have a 'small' frame so even though i am normal weight i look fatter.

i am 113lbs so I would like to lose 10-15lbs. what size do you think i will be then? two?

i am already dieting but what exercise should i do? i think cardio would be best to burn fat. would running a mile everyday be effective? what would work better?