By the time we get married my fiance and I will have been dating for almost 10 years (high school sweethearts). Over that time, I have grown very close to his younger sister. Up until recently, I thought I knew which friend to ask as my MOH but that's a long story. I would really like to as my fiance's sister to be my MOH but she will only be 17 when we get married in a year and a half. Is this too young and would this role be putting too much pressure on her? Thanks!