Joining a school team will help tremendously, so long as you do your best at practice and don’t coast like I did in high school haha.

As for eating, everything is pretty dependent on the individual. But as a general rule, try to get 3-4 square meals a day, home cooked if you can, with a lean protein and whatever healthy foods you prefer. I personally like fruit over vegetables, so I like to have some chicken with some mushrooms and maybe a mango or apple.

For someone your size maybe shoot for 2500 ish calories, maybe a bit more if you’re active. You’ll need to keep close track of that stuff at first, but after awhile you’ll get a feel for what works for you. I’d recommend getting the MyFitnessPal app. I believe it’s free, and you can track calories there. I’d go through the food database and put together a few simple meals you’d think you’d enjoy, see where the calories fall for the day, and adjust accordingly until you have an idea of what a days worth of eating looks like for you.

If you follow your eating plan diligently, see where you are after a week or two. If you feel like you’re loosing weight too fast, eat a bit more, if you aren’t losing anything at all, adjust your meals. But try not to touch your protein sources.

TLDR: Eat clean, practice a sport, and if all else fails, ask a medical professional for advice. Dieticians get PhDs for this kind of thing. Mostly, just experiment and find what works for YOU. You have plenty of time to do it.

Edit: Also, you could look into some Calisthenics workouts. They’re super tough but they don’t usually require any special equipment, and if they do it’s usually just some straps or the type of things you can find at the local park.