OK, have been in a similar situation myself recently, so I will give you my view, YMMV. Was given the indication a friend was interested - also a nice, hugely intelligent good looking person, so asked him out - he agreed enthusiastically, but I didn’t hear from him again until the day of the arranged date - by which time I thought we were not actually doing anything. We then developed a pattern where we’d do something, then I’d not hear from him again for 2 weeks or more, other than some random texts. So I assumed he was not interested, other than I was hearing from mutual friends that he thought we were dating.
I gave up, and he didn’t seem to chase me - I starting dating someone else, and flash forward to New Years Eve when it was clear he was still interested.
So the analysis - I did take the view that ‘he was just not that in to me’, which is apparently not the case - have been told by friends he is acutally really awkward around girls, and has not dated in a long while - i.e., it’s not that he’s not interested.
However (and this is the key to my post) - his dating dynamic simply did not suit mine. Remember that dating is about finding someone who’s personality and temperament matches what you want. I decided I was just more high maintenance than his temperament provides for. Realistically, regardless of whether the interest is there, if I am going to spend my whole time feeling neglected, or dumped on, it’s not going to be a relationship that works for me.
I think you expect a level of contact that most people would - following up on offers, apologies if the date needs to be broken etc. I have to say, regardless of whether she likes you or not, her behaviour seems to show a lack of basic consideration - which I would not be able to handle. It’s up to you as to whether you think she’s worth overlooking this for.
And if you think she is, I think you should not be passive about it. I think next time you see her you need to point out that her breaking these dates without warning or apology is upsetting, and if she sees this going somewhere, you’d like more consideration.
If she is ditzy, this will be a wakeup call, and she can do something about it if she knows it’s bothering you. Perhaps other people have just put up with it in the past - attractive people have reps for being able to get away with this sort of thing more!!
And if not, you’ll know how she feels, and you can move on. You mention you like to be guiless and open when it comes to dating - here’s a good situation to practice that.
Good luck!