By mc4lifes from Sydney, NSW
There is no "set age". Some start as early as 9 and others into their late teens.
If nothing has happened by age 17, I would suggest a trip to the doctor.
I started when I was 8, and my daughters at 11, 13, 14, 15 and 16.
Diet plays a factor -research has shown that girls who drink a lot of milk with hormones in it tend to start earlier, girls who don't get enough iron start later. Weight plays a factor as well, as being underweight or overweight will delay or stop it (athletic women often stop during training).
Don't pressure her, it isn't anything she can control, and don't make her self conscious or worrisome over it. Actually, having one can be a pain in the rear end when you are young, so enjoy life without it! She won't have to worry about swimming or overnight slumber parties without it!
I would have the discussion with her, and make sure she has a couple pads with her in her purse, so that if the time comes to start when she isn't home, she is prepared.
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