What to do if i'm 16yrs old and i'm very short, help me?

It depends!: Size if often related to genetics. Short parents usually have short children. Size must be related to a growth chart -- look at height and weight over time. If there is really very little growth, see a pediatric endocrinologist to evaluate if this is genetic or normal, or is there really a growth hormone deficiency that would benefit from therapy. If no problem, encourage good self esteem!