Weight question! serious answers please!?

so let's make a long story short and say i was a cheerleader the season ended and in just a couple of months I started to gain weight rapidly. i'm 14 years old and right in between 4'11" and 5' I weigh around 100-105 pounds. I have always been skinny but muscular and now it's all fat... I really want to lose this weight. as fast as possible but in a healthy way so I won't gain it back or injure myself. I'd like to know what I should eat and drink, how much of whatever it is that I should be eating and also how much, and what kind of exercises I should be doing. most of the weight went to my stomach hips and thighs. thank you so much. 10 points best answer(: