Prematurity / height. I can get help?

I've been searching all over the internet, asked all my doctors, and they couldn't even answer this question for me. I am a 17 year old male I am 5"4, I was born 2 months pre mature and 2.5 lbs at birth. My dad is 5"11, my mom 5"3. All my cousins are taller than their parents, I even have cousins who's parents are no taller than 5"7 and they're 6"1. Height is not a problem in my family why am I short ? Is it because I was pre mature? I've asked all the doctors I can ask and searched it a million times, I can't seem to find the answer, can someone please help me. Does pre maturity affect the height/ development of the child. Note - I am not physically or mentally disabled in any way, I am just short. Please I need an answer/ solution to the problem. Is there Anyway I can get help??