tips for incoming freshman?

i start my freshman year in a week or two and what are some tips for a fat kid lmao. im not extremely big or wtv but i am sort of un athletic and im nervous about PE class. a lot of ppl say that others dont care but i wanna know how i can prevent embarrassing myself or get tips on becoming more athletic.
ive been going on alot of walks/weights and cutting high calorie foods but i cant do a push up for shit.