16 and want to loose weight ,quickly as possible for prom?

Im 16, about 5.10 and i am over weight and i really want to flatten my stomach quickly as possible because prom is in about 3 weeks and i am going on holiday straight after. So please help because my date is skinner than me and I would love to impress her …..So what can you recommend so that i can loose weight from under 3 weeks?

I am afraid you are not going to alter your body shape in 3 weeks even if you do lose weight.