Gym/ Fitness plan for a newbie, thin and weak woman.

I am thin, 5'5, 50kg and can't do a sit-up to save my life.

I am in college and nakakahiya tuwing P.E. I want to die.

Mabilis ako hingalin, can't do a proper pushup, di kaya mag treadmill for 10 minutes straight. Everything feels heavy kahit 5kg na dumbbell

I can walk or hike for hours but thats about it. Mababa naturally appetite ko but I can adjust.

Di ko alam if I should even enter the gym, quite frabkly nahihiya ako kasi I also don't know what and how to use.