My maternal grandmother says that she was in her late 30s/early 40s and done with menopause, which is possible. My mom was in her early 50s by the time she began menopause. I remember her surprise and a conversation about the doctor putting her back on the pill as she remarried that women can bear children at 50.
My paternal gram had had a hysterectomy in her early 40s.
So, it seems really tough to pinpoint what's the approximate age for each person. Just when I begin to wonder about perimenopause for myself, nothing. I'm curious for myself because "they say" that it can release my dormant illness. So I'd like to guess when and if my health crisis may(or may not) arrive care of this stage of life.