My mum and I both started our periods at 12.
We both had exactly the same problem with giving birth (cervix wouldn't dilate past 3cm).
She started menopause at 39 (not 100% sure what she means by that, will question her further). I'm nearly 40 and have previously had extremely regular periods of 28/29 days. I'm 9 days late in my current cycle which is unheard of for me. Absolutely no chance of being pregnant.
I know 39 is very early to start menopause, but do you think this could be it? If so, do I need to do anything or just let it run its course? I'm shamefully ignorant about all this.