BBT Charting

Tiffany
I JUST started charting and am super confused. From what I've read, it takes awhile to get the hang of it, but I have a question for you all...
​Should I expect fluctuations from day-to-day? How much? Also, day 1, I came in at 96.1 degrees but it seems like the Glow Chart won't recognize a temp that low. I checked it twice. Is that a concern?