BBT question

This is the first cycle I’m tracking my BBT. My temperatures before ovulation were 97.20s. Two DPO, I went to 97.53 and then 3 DPO went up to 97.79 and had been above that since yesterday. Today, I woke up at 5 am and I was 97.64 ( I usually check around 6 am). I woke up again at 7 am and was 97.75. I am 7DPO today. I would assume the 5am one is the more accurate, since I was asleep for longer before. My question is is this a normal fluctuation or could my temperature be starting to decrease before I get my period?