That isn't being oversensitive. It is them being ignorant.
Do not blame the people who struggle with the change, but do blame people for them taking to long to change. I think it depends on how much it bothers someone as of how quickly they changed. I even met a transphobic person but when I came out and asked him to call me by my new name, he did so instantly. He didn't took me seriously and was joking about it, but on that moment he changed my name and never made a mistake anymore. While as for my family who struggle with it they still struggle after two years.
Friends who it didn't matter it took a few months. People who it did bother, even if slightly, they still pronounce incorrectly.
Just how it is. And older people have a harder time with it.
But all with all, in my opinion someone whom you only have known for a year has no excuse for it taking so long. Only thing I would advice you to do differently is to talk to her personally. Not in a meeting. It is personal. For you, and seems to be for her also. So keep it personal and try to solve it with her.
It is a valid reason wanting to move though .. my main reason I am moving out really soon is because my family misgenders me, everyday, every hour, every minute. All they bothered to do is calling me by my temporary androgynous name. It makes you annoyed and your house should be to relax, come at ease. Not to feel stressed and feel as if you are walking on your toes.