Is this normal for me?

Im 5'5 and about 117 pounds, I want to be skinny SO so soooo badly! I want to be about 105 or 100 pounds. Can I lose the weight in about one month. I want to be a dancer so is 100pounds going to be to heavy? When I hear about Lindsay Lohan being 105 I go ballistic. Im pretty sure Im shorter than her. Am I obese? My mom always says how I need to lose weight so how do I do this without starving myself. Is 100 pounds alright for a pre-teen dancer?