The fact that you got an emotional reaction at all is pretty encouraging, in my opinion. It was the right time to 'do something different'....
I might ask her how long she intends to stew on this, if she meant a couple days or even a couple weeks I could see giving her that since the letter was such a departure from your usual interactions.
But if she says who knows? Or spring, or whatever, then don't give up the big step you took giving her the letter by letting her wait that long....just my opinion. Timing is everything, strike while the iron is hot, etc etc
If you give it a month or two, the message is watered down and loses its punch. She may just wait and hope it blows over if she can put you off that long....
But I think it is great that she explained a little more about the C comments, and that she said it was beautifully written...
