libby
i am a 25 year old woman who did not start my period until i was 16 .my doctor said it was normal my mom didnt start hers until she was 16 either.it runs in some families to start late.also if you are very athletic your period may be late starting and also if your experiencing a lot of stress or possible abuse this can also prevent you from menustrating.i would just not worry about it right now .if you think there are possible stressors that is the cause of it try to eliminate them .however if you are 17 and still dont have a sign of a period than your doctor should probably run more tests. oh yea .starting late did not hinder my fertility .i had my first child at 19 and my second at 23.there are benefits to starting late such as low risk factor for getting breast cancer. all should work out fine. good luck and god bless.