Scared to show my fat?

ok, my year end school excursion is at sunsplash, normally happens every year. im in 6th grade, so i can finally be able to go. but, i like wearing 2 piece, but i dont like showing off my belly on and stomach. it feels embarring and showy. should i like put a shirt over and a shorts as well? i have billions of friends coming and they feel the same way. overall, i HATE my thighs. help?