The average age of menarche is considered to be between the ages of 11 and 14...Research suggests that the average age of menarche has fallen over the last century, due to a number of factors including improved diet, better health care and possibly the increase in oestrogen-like substances in the environment.
Though this website talks about 11 to be the minimum,it is actually about the current generation-It clearly says that this is subjected to many factors.and to try to correlate it with some one lived 1400 ago is to ignore all these factors.
