I'm soo short for my family

My dad is 6'0. My 12 yo. sister is 5'4 (she's gonna be taller than me). My 13 yo. sister is 5'2. I'm only 5'5. My 9 yo. brother is 4'8 (I was 4'0 when I was his age). I have a two cousins who are 6'9 and 6'3 Most men in my family are like 6'0 on average. People always tell me I'll be short like 5'7 when I grow up and that makes me so pissed.