13 year old 4'9 and 140 pounds, seriously need to lose weight.

Ok. Like the title says, i'm 4'9 and weigh 140 pounds. This took a whole load of balls to post here, even from a throwaway for my young age, but looking through the comments the people here seem kind and positive. I walk for about 40 minutes every day to and from school, and my BMR is 1573.7. My total calorie needs to maintain my current weight is: 2163.8375, to achieve that I multiplied my BMR by 1.375 as I'm lightly active, have 2 periods of P.E per week at school, and play football (soccer) at lunch with my friends.

Lately though, I've been getting seriously bad leg/knee pains, one trips to the doctor's later and I find out that it's a problem with my hip that usually occurs in overweight teenagers going through puberty. One of the joints when I was born in my hip basically isn't completely fused to one of the bones in my joints, and apparently the bone has lightly slipped and that's what is causing the pain. Because of that, I can't jog/sprint without pain. I wasn't so overweight before year 4 (think that's 4th grade (8-9 years) in America, and just piled on a load of weight from year 6-8.

So r/loseit, can you reccomend me a suitable diet to lose weight please? I'm currently looking at the ketosis diet.