Good workouts??? Want to loose fat and weight and gain muscle!?

Im 14 years old, 131 lbs (last checked 2-3 weeks ago), Im 5'3" ish. I know im not the healthiest of people but I want to fix it! Judging by my family I have the genes to get over weight and I DO NOT WANT TO!

I wold do rec sports but our county doesnt go over 14. Im going into high school and im going to be on the swim team (no cuts) and I want to be in shape for it! Please help with a healthy diet and workout!

Plus right now im at my grandparents now and you know how that is... candy everywhere. :/ Im resisting somewhat but its hard! Ive been here for about 3 weeks now and i leave in a week!

*nothing that will hurt my back cuz i have sculliosis. :/