I just turn 40 in Aug. I have always be consistent with my period, normally around 26-28 days and lasted four days when I was younger. Over the last few years my period has gotten shorter by a day. But still around a 27 day cycle.
By the way I have never had kids.
Over the last few years I have had minor changes in my body. Started to get "chin" hair, my feet our always cold unless out in hot sun. I get these "pre" announcements I will be getting my period then nothing happens for the next few days, then it starts. Also I have experience minor incontinence, like I'm not able to hold my bladder like I use to. It's very much controllable. I just don't pulled how long I can wait to go to the bathroom. Which I normally don't do, even in the few times I though I had enough time. I had to run to the bathroom quicker then I thought. Doesn't happen offend but it is noticeable to me.
As for my period I have been late going on 7 days this month. But every morning or late after noon I get the "feeling" I'm going to start, then nothing happens.
I do have all my lady parts and never had children. For the last 37 years my period has always pretty much been on time. Maybe late by a couple days or a day early. But I have never skipped a period.
So just see what if anyone starts going through menopause this early.