This sounds like a really difficult situation. I know I would not be happy to end therapy in such an abrupt way and, as you say, it sounds like maybe you were looking for a reason to cut ties before they got too strong.

I don't like her telling you "you're not ready" when you feel that you are, though. It seems to me like she could find a way to discuss it with you more and think about how you might get ready or know you're ready. The slamming the door thing seems unprofessional too.

Still, if you want to go back to therapy with her I think it would be worth setting up at least one more appointment to see if you can work this out and compromise like you want. If you can, great. If you can't, at least you won't wonder if it might have worked.