How to know if i stunted my growth?

No way to be certain: You're an adult; it is impossible to know what height and body type you'd be had your growth been affected as a child. The size and body types of your parents, siblings, and children can provide clues, as can historical information about diet, activity, and medicines as you were a growing child. If you're concerned about a congenital problem and passing it on, see your doctor or a geneticist.