Je'Wan Pelt answered 4/26/2011 How Tall Are 12 Year Olds Supposed To Be? Around 5,2 when I was 12 (1 year ago) I'm a boy and was about 6,5 and weighted 145-160 but I'm 13 and 6,8 my dad is tall 7,4 5xgrate grandfather was 7,10