How can I get rid of my chubby thighs, fat calfs, mive stomach, huge arms?

Hi, I am a 13 year old girl. I weigh 62.5kgs (137.5 lbs). That is big I know. What I want to weigh is about 41kgs (90 lbs). I eat healthy. I excersise. I do strength workouts. But still I find that I cannot lose the weight. I do 9 hours a week of gymnastics, I'm the biggest in the team and I'm really trying to get rid off these excess kilograms. One of my main problems is that I cannot control my eating. I wake up and I eat 2 weet bix with milk and sugar. I keep saying to myself, I'm gonna eat my weetbix tomorrow morning with no sugar, but then when I wake up I find myself putting buckets (not literally) of sugar on. I finish my breakfast, I go to the cupboard and I get an orange. I eat about 3 of those. Then I eat about 3-5 carrots. Lunch time comes, I eat about 2-3 servings. I eat heaps until tea comes when I eat about 2-3 servings. I make dessert (peaches and yoghurt), and I put the most of the tin in my bowl. I keep trying to lose the weight but I just can't stop myself from eating. My mum yells at me for eating all the bread. I am embarrased about my weight and don't want to tell mum about how much I weigh. Today she wanted me to check my B.M.I. but I had to lie to her and tell her that I already had. I really have to lose these kgs fast else she's gonna find out sooner or later how much I weigh!! Please help!!