Im 14 and want to loose weight!??�?

How can i loose weight? Im 14 and i weigh 100 pounds and im VERY short for my age since i am 4'11. I want to be at least 90. I have belly fat and my cheeks are so chubby. Even my brother and mom call me fat. And it doesnt do any better that my older sister is so pretty and skinny. So is there any way i can loose 10 pounds?and wat type of exercises can i do?? I also dont eat breakfast since i dont have time in the morning during school days and i rarely eat lunch since i dont like school lunch. I just eat dinner when i get home and i tend to eat alot of junkfood. So please help!! Thank u?!