How can a 13 year old loose weight FAST? please help!?

Hi... I am turning 13 in less then a month... So techniquically I am 12 but almost 13. I am 5 feet, 2 inches. I weigh 104 pounds. I just weighed myself last night and was shocked! I was happy with my body until now. And now that I know how much I weigh, I just feel very fat and huge! And I am a cheerleader and volleyball player. I dont eat junk food very often. Everyday I go up and down the stairs of my entire house 20 times. And I do this work out called turbo jam. And I do 300 cruches. And an ab work out, DVD, thing for that too. I skip breakfast almost everyday. So I dont understand how I can weigh this much! I feel huge!! In cheerleading, I was the flyer last year. And my coach had me in mind for being a flyer this year, but I dont know if her mind well change, once she sees that I have gained some weight! I have to be the flyer, because Im not strong enough to be a base. And I dont want someone to take my place. I just want to feel good about myself, and be the flyer on my cheer squad. I have about 2 months until the summer is over and cheer season starts. My goal is to be 82 pounds or less. That means that I have a lot of weight to loose. Somebody PLEASE help me!!!!! I have about 2 months, but I would like to loose weight A LOT faster! Please some one help me. I really need to loose some weight. Thanks sooo much!! And also what is the average weight for someone who is 13 years old and 5 feet, 2 inches? And how many calories per day should someone my height and weight have? Thank you so much! Somebody please help me! Thanksss!!!!(: