Talk to Endocrinologist on Looks Much Younger Than Actual Age / Short Height

I am 24 years old, but I appear much younger (in appearance from look) than my actual age. Most people assume that I am a school student or around 15 years old, and consider me like a small kid. My height is 4 feet 11 inches. I want to know what could be the possible reasons for this — whether it’s hormonal, nutritional, or genetic — and if there’s anything I can do to look more my age or improve my overall growth and appearance.