Bbt question

Liza • 👦🏻 5/5/16 👼 8/13/18 🌈 👶🏻 12/15/19 👧 12/4/2019 (our 🌈 baby came early) 🤰with baby number 3

Ladies, I have only started tracking my bbt this month-it’s been about 3 days- yesterday my temp was 96.6 and today my temp went up to 97.63- what is happening??? I’m so confused when it comes to bbt. Please help??