I am 5'2 and weigh 100 and i am 16 could i become a gymnast?

Why not? Gymnastics is about skill, not body type and weight, although 100 lbs for 5'2 is just about ideal for a 16 year old. I'm 5'2 and 100 and 13, but I've been doing gymnastics most of my life. It'd be harder to start at 16, but it's never too late to try anything!!