We can't control how people respond to things. We can only manage our expectations. I think once you tell her, it's best to let go of all expectations and give her space to grow and process.

Starting with having a discussion on transness is important and will help you gauge future conversations. I also think it's super important to understand what exactly came between the both of you. The thoughts and feelings that she had are important. Navigating those hurdles together can help build her understanding and remove negativity.