Bbt help

I just started keeping my temps it's been 3 days and I take it right when I wake up before I get up drink anything and the same time everyday. My first temp was 97.1the next day it was 97.0and today it's 96.8. Is that normal?? I don't understand why it's dropping and not just staying a normal temp everyday. I completely understand if you ladies think ugh omg your dumb!! But I'm confused lol