Typically junior bridesmaids range in age from 8 - 14 but if his sister is small or less "mature" looking she could be a junior bridesmaid. Being a junior bridesmaid would mean that she has less responsibility for helping to organize showers and standing in the receiving line. If she is a normal, nearly 17 year old girl then I would suggest naming her a bridesmaid. Top Wedding Questions Forum Moderator - "Write your sorrows in the sand, your blessings in stone".