I started my periods at 10, had my children at 39 and 41. I wouldn't correlate onset of puberty with reproductive age. In middle ages (when people were not as big as now), brides were 11-12 year old (one staining was enough to marry and bear children, regardless of how under-developed their bodies were).
The more accurate predictor is your mother, you need to know when she started (maybe not yet) going through "the change", and most importantly - when she ended the process (surely she still hasn't). That menopausal process is more complicated than puberty, it lasts for 10-15+ years, with stops and starts. So many "oops" (accidental pregnancies) to women who considered themselves to be in menopause.
PS: I'm sure at 27 your female organs are going to be pronounced in excellent health