At what point to I drag DD to the docs (periods)?

[ZombiesAteYourCervix]

She is 15 (and a half) and hasn't started her periods yet. She is fairly skinny and used to be small but is now about 5 ft 4.

Do I wait another 6 months or so? or do something now?

I didn't start my periods until I was nearly 16 (I was the second to last in my class to start!) so it's certainly not unheard of. When did your own periods start, as my mum, sister and I all started late. If she's very skinny it could be to do with it though...is she in your opinion under-nourished, ie dieting etc or is she just naturally skinny but with a good diet?

i was 13. DD2 was nearly 13. She has a good diet (for a teenage girl anyway!). She is active and dances but not a huge amount.