LL, welcome. Sorry you have felt the necessity to post, but posting really helps.
Sadly, now that you have set your limits, she might push back harder and uglier. I hope not, but...
It would be nice if we could just set a limit and be done, in our heads and our hearts. Unfortunately it is rarely that clean, when dealing with a Difficult Child. There will be ups and downs, but for what it's worth I agree with everything you did. My regret is not doing it sooner.