Whats the best and fastest way for a 13year old girl to lose 1-3 stone / 2-3 pounds a week?

Im around 12stone and around 5.6/5.7ft. im tired of feeling fat and being bullied by stupid idiots in my class just because im not like a size 6. i dont want to be, i just want a flat stomache, great legs and toned arms, and a less chubby face. i dont exercise that much because i get embarassed in public but i am prepared to exercise at home when no-one or only a couple of people are in. i've heard that drinking alot of water helps so im going to start doing that. Also, i heard keeping a diary of the things you eat will help keep you on the diet. i will try to cut out all junk food by getting my mum not to buy them. You cant eat them if its not there. :) i started puberty quite early so my hormones go crazy sometimes and i want to "eat my feelings" so i need advice on that. anything will help, just pratical things, because i cant go to a gym and i dont want to go swimming, as i hate my body in a swimsuit. just home rememde's would help. thanks.