More frequent periods in your 30s?

So

Is anyone else experiencing this. I recently told my doctor that my period occurred every 28 days. Yesterday I checked this app and noticed that it is actually occurs every 21 days. I know this is within the "normal range". However, I can't help but feel like my hormones are starting to run the show. I'm either pms cray cray

, on my period or about to ovulate. I have one week per month of feeling normal. I'm a mom of one ds (not on birth control) but only 31 so I hope this balances out at some point before my 40s. Anyone else experiencing more frequent periods in their 30s? Are you concerned?