Help! can I lose weight with "I can make you thin"?

Hey, umm. well, this is my story. I'm 13 and im about 5'4. I really want to lose 10-15 pds by the end of summer. If I follow the rules do you think I could lose it? Does it really work? How long will it take? I am willing to give uo ALL sweets (I have a strong will power and I have done this before or 40 days!) Thanks for your help!