Period calendar

So I was on birth control for almost 10 years and I never had my period (unless I skipped some pills) I never tracked it cause well I had nothing to track.

I decided to get off BC cause I wanted to know my body without those hormones. (Btw I love being off BC)

Anyway, when I started logging I didn’t know how long to put my period so it did 7-8 days. Well my period is only 4-6 days and when I change it in the calendar the ovulation days don’t change with it. So I have like 4-5 days with “no ovulation” then right after the 8-9 day it says I’m ovulating. That just doesn’t seem right to me.

Is there any other way to change the ovulation days besides the bbt or the ovulation test?