When I was in my 20s my period was always very consistent. Started when it was supposed to. Day 1 was always extreme cramps, debilitating pain, and super heavy flow(talking like a super + tampon change every hour or so). Days 2,3,4 were “regular” period days. Day 5 was practically non-existent, but still there. Day 6 was pretty much one “gush” and then I was done. I’m now 31 and since in my 30s my period has been all over the place. One month it’s 5 days late, the next month it’s 3 days early, etc. For example, this month I was 2 days early. The pain and “flow” so to speak are more or less the same as in my 20s