again with the flakes

Oh, if only the flakes I had in my life were just happy little corn flakes (these are my favorites, three ingredients, eat that Michael Pollan...no, really, do! I think you'd like them, Mr. Pollan. I'm a big fan of them AND you).
Unfortunately, the flakes mentioned two posts back indeed did as I expected and flaked out on me. Because they are flaky hippies and it is their nature. It wasn't malicious, it was just...lame and very rude. I had a whole dinner done - honey lemon roasted chicken, veggie salad, potato and veg au gratin and black bottom cake - and when 5 pm rolled around, they were nowhere to be found. Nor at 5.15. Nor 7. There was no call, no text, no email. Just a simple no-show. Needless to say, my pregnant ass bawled like a little six year old, and then ate all the roasted honey-crusted chicken skin out of spite.
So today (five days after said dinner was scheduled and bailed on), I get a facebook wall post: "Oh I am so sorry, I'm so horrible, I just couldn't handle going out for a while, I guess I should've at least called, can we hang out". Now... from Sunday night (when Ma and Pa came over for carbonara made out of the roasted chicken and to "help out" with the cake) until today, I thought I was okay with this situation - my friend is a fucking flake, she's always been a wishy washy flake, and she will continue to be as such and there is not a whole lot I can do about it. We're not bff or anything, but we've been pals for about ten years at this point in time. Flakiness was manageable, nay, expected, back then in our high school years, but now.... No. Now it's time to have manners and a capacity to plan. SO. I am mad all over again now, because she apologized.
It's conflicting, I feel like a dick, but I am so mad that I don't care, but then I would like to graciously accept the apology and move on. I know it's not my place to reprimand or lecture her, she's an adult. I don't do passive-aggressive punishments, but OH MAN am I tempted.
So do I wait until I've simmered down to accept, or do I give her a quick "we're cool" and wait until I'm calmer to try to make plans? I understand she is how she is, and so in being her friend and knowing/expecting that, do I even get to be mad here? I don't know how to proceed. I like her a ton, but I am fumed, big time.
Being a gracious adult is tough work, man.