Low BBT

Dana ☀️ • 32. Married 7.12.13 • Mommy to Elliott 👧🏼 3.5.16. Due with baby girl #2 12.12.18
I just started tracking my BBT about 2 weeks ago. I have 2 different thermometers that I have been using and my temp has never been over 96.8 but once last week on the day I started AF it went up to 97.2.   Is it normal to be that low everyday?