Facial hair (moustache and beard growth) starts around the age of 13 to 17. It takes around 3 years for complete growth.
Testosterone hormone is the major cause of the facial hair. FSH and LH hormones also help in maintaining the testosterone levels.
Testosterone production causes the secondary sexual characteristics to develop on males.
If any of the secondary sexual characteristics are not developed or if you have a feminine characteristics then you might have low Testosterone, which you need to get evaluated with a endocrinologist.
Lifestyle modifications and proper diet helps In testosterone improvement which will help your facial hair to grow.