Kids and teens grow and go through puberty at different times. For girls, puberty usually begins between ages 8 and 13. For guys it often begins a bit later - between 10 and 15. You must have observed some teens develop a lot earlier, whereas others develop much later than other people of the same age. There's a medical reason why some people grow more slowly than usual.
Reasons of slow growth:
Genetic Reason: If you're short, you may just have familial (genetic) short stature. Like short parents tend to have short children.
Lack of Nutrition: Not getting adequate amounts of protein, calories, and other nutrients in your diet can also cause growth to slow, as well as a number of other chronic medical conditions such as kidney, heart, lung, and intestinal diseases.
