Sorry if I put this in the wrong place, I just came across this article. I started my periods when I was 11 and this is making me very concerned, particularly this bit:
Women without children who had their first period before 12 were five times more likely to reach menopause prematurely than women with two or more children, who started menstruating at 12 or older.
Often, these women had difficulty falling pregnant, Mishra says. This suggests there is a link between early menstruation, infertility and premature menopause. If a woman goes through menopause in her 30s, her fertility could start to decline in her 20s, Mishra says.
www.newscientist.com/article/2119117-starting-periods-at-a-young-age-is-linked-to-early-menopause