Remember, the average across a population says absolutely nothing about the value of one data point. One girl born in 1980 may have started at an older age than one girl born in 1960, but the AVERAGE age for girls born in 1980 may still be younger than the average for girls born in 1960; the two individuals are just at different points on the curve for their cohort. (Can you tell I am a data analyst?
Another thing to remember is that half of your daughter's genes come from her dad's family, who may have a different puberty timetable than yours, and she might "take after" anyone in the family, due to recessive genes and so on.
T One thing that puzzles me (being interested in puberty and how it influences people's life experiences, and thus tending to start conversations about it w/friends) is that almost all women remember their first period vividly and often recall the exact date, whereas about half of men have no particular recollection of their first ejaculation, whether it was via wet dream or masturbation. I can understand why the date is so memorable for menstruation: because of the emphasis on tracking your cycle. But it seems like ejaculation, the "now I'm a man!" event, would be memorable as an experience.
: They seem to be better able to remember when their voices changed or they started shaving or other more "public" (one hopes!) aspects of puberty, whereas for women menarche seems to be the most memorable step. Any idea why that is?