Why is my my cousin is short and my uncle is so tall and I'm tall?

My uncle is 6'4 (my dads brother) and my aunt is only 5'5. My cousin who is 16 is only 5'3. My bio mother is 5'8, my dad is 6'2 and I'm 6'1 and a woman. What the hell?!!!
My stepmom is 5'4 and my younger sister is 5'6.
Why am my so tall? I mean my little cousin is short and my uncle is very tall. How can someone have a tall parent but is short. Some say they envy my height. I'm the tallest female in the family (mom and dads side).
My parents aren't that tall and I an over 6ft.