Im 13 and 5 ft. Not Sure on height but its that or 4'11.5. Anyway I need help gtting my Bkini Bod back?

I need exercise tips and healthy foods. I have 2 months to lose 25 pounds. 25 pounds then ill look fabulous in my bikini again. I got a little belly and actual hips or thighs. I was bone and muscule plus skin, but now im FAT,Muscle, and skin. I dont look like me.I dont care about having some fat but not alot. Help pls. I hate winters. You gain weight b/c there is nothing to do. Ugh. Help pls.