Aw Okay if she sleeps with you then I wouldn't ever worry about going to bed if she is still in the triple digits at +3-4 because if she starts going too low overnight it is very very likely she will let you know.
Autumn doesn't sleep with us, we've tried to get her to, but even she will come in and wake me if she is lower than she is comfortable with. So if Frankie sleeps with you and she starts going too low I'm sure she will wake you up with a "Hey Dad, Mom Fud Please!" Or at least just go eat if there is food available for her, cats are remarkably clever that way.
Mel, Maxwell, Autumn & The Fur Gang