I am 5'6" 130lbs and turning 15. One uncle is 6'2" another 6'1". I have a cousin 6'4". The ones on my dad's side are average and i dont know them well. But the shorter ones grew early (13ish) and the tall ones grew at 16-17 years old from 5'2"-5'6" to 6+. In my family, the later you grow the taller you grow. Might be similar in yours.