Im 14 years old wanna lose weigh?

im 14 years old and i weigh 103 pounds and im little for my age lke 5"1" and i wanna be 85 pounds by june.help. befor bed i do 3 sets of crunches different kinds, 3 sets of push ups, 3 sets of legs workouts, and everynight it changes from 3 sets to 4 sets then back to 3 sets, i just started on friday and i wanna know something else i can do, and i dont wanna go on a DEIT . please give me some advice or some websites. thanks :)