Lucy Walker answered Bubbles 513's question 5/3/2012 I'm 15 And Haven't Started My Period Yet. I'm Worried I Won't Start. My Mom Started When She Was 12 And All My Friends Have Started. Is This Normal And Is It That Everyone Is Different? Like What If I Never Start? I am exactly the same!! I weigh only 98lbs so I'm hoping this is why. I'm also a full time gymnast so would this be the reason why I haven't had my period yet?