I want to reform myself before school goes back. any tips?

i'm 13 years old, i weigh 117, im 4'11. just incase you're wondering, thats as tall as im going to get! i don't only want to lose some weight, but i want to be healthier. i need tips on easy ways to do this. i can't really jog or run where i live so i need tips besides that. thank you:)