Her reaction probably came from a place of insecurity. Another person in the thread hinted at this. My personal feeling about her is that the existence of someone outside of her perception of gender made her feel threatened. Your description of her volunteering how much she had worked to erase her old gender seems indicative of this. She's invested a lot into fitting into her strict ideal of gender and femininity, and meeting someone with such a radically different view of gender than her own challenged her and made her feel uncomfortable, and it was easier for her to simply dismiss it than to have to accept you, and therefore, reconsider her own ideas.
It says a lot more about her than it does about you, Shawn. Don't let it get you down. *hugs* You definitely don't have to be "one or the other."