Slim fast question please answer!?

ok so i just got everything and am starting tomorrow i already eat very healthy, am a vegetarian and exorcise everyday but the weight just does not come off! i need to know if it works and also how long it takes to loose the weight and about how much you loose. i know it doesn't work in the long run but i just need to get some weight off now and then ill have motivationn for other things. please answer! by the way i am a 15 going to be 16 girl and wanted to loose weight before school. im not fat just not completely happy with how i look