Confused about bbt . 😔

My temp is 99.02 and I'm 12 dpo . My temps have been up since ovulation. & I've been having symptoms all over the place . I'm trying to hold off testing until af . I tested few days ago but bfn . I might've tested too soon since I'm seeing everyone getting bfp at only 8dpo . My mom didnt get a positive until she was 2 weeks late on her period when she had one of my siblings .

I'm still a bit confused about bbt charting . But I've never had a temp at 99.02 while ttc . Can someone explain this?