no your perfectly fine. my friend is a год younger than me and he's around your height. that means he's...fourteen? i can't remember. I always mistake him for a senior by accident even though he's still in middle school. ^^ ' But your okay. Don't let your height be the only thing to worry about. It matters about what's inside!! :D (eww, im soundin mushy-gushy again...)
I don't think Ты are i actually think that is kinda short (if Ты are 5'7) but i have some really tall relatives. Though i am 14,5'6, and still growing but i think when i am finished growing i will be around 5'9.