NO!!!! Don't crash diet. There is no good way to crash diet.
Don't worry about it so much. Just relax, get some exercise, cut out the junk food and pop and I bet you lose weight. Can you join a sport at your school? Even if you're not the best on the team, the practices will benefit you because you'll be getting some structured exercise.
You're so young that you're probably still growing. One of my brothers was overweight until high school when he started playing sports and getting taller. Now he's lean and muscular.
I hate to tell you this but there is no miracle way to lose weight. There's no way to do it as fast as you want it. Just go out and have fun with your friends. Go play basketball, soccer, ride your bike, anything that gets you moving.
~teresa