Done with baby father's family

So frustrated at this point. Baby dad's mom said she'd bring me to my 3 hr glucose test. I seriously said THREE HOURS in my message to her and she said she'll pick me up at 7:30am. About a 1/2 hour later she sends me these. Even if she has a "meeting", then there'll still be plenty of time to take me back home and get to her meeting as I'll be done between 11 and noon. I did give her permission to be in the room when he's born but now I'm starting to rethink that as this isn't the first time she backed out of an appointment for HER grandson. And I have a feeling that she'll back out of seeing him being born because of her history. I'm 37w1d today and I want to get the 4 hr Glucose test done to make sure sure I don't have GD