How can you lose 1.5 lbs a week?

okay i am 13 years old and is 5' .5'' and is 13-115 lbs!! i am not fat nor skinny. i am on the brink of thin and cubby-ish but i am somewhat very musscular. but no dought i have some fat of me!!! i want to lose weight around 10-15 lbs in the next three months in time for summer!! i am thinking of starting the diet/lifestyle around feb. 18th to june 5th. how can i lose 1.5 lbs to 2 lbs a week without starving myself??? i have gymnastics monday and dance tuesday through saturday and rest sunday BUT i want to get ready for track in the spring so how can i incorperate training for that so i dont seem stupid during the season!??? SOO i am really asking how can i lose 1.5-2 lbs a week with out starving myself AND how can i get in shape for track with my schcdule???? THANK YOU SO MUCH!!!