I'm 48 and have had heavy periods. My last one started on 6th January and I basically bled on and off for about three weeks!
I do have a fairly regular cycle but there is still no sign of February period!!
I use the fertility friend app (back from when we were ttc 10 years ago!!) and it says I'm on day 40. Input all the data from October into a different app called clue and it says I'm due tomorrow!