Wait so you're not out to her?
I found my mom did the same thing, however it was the more I became more like a typical guy, mainly because of the changes on T. I know what you mean, it's hard to just ignore it or not let it bother you so much. When my mom does this I get angry, and I stop talking to her. Once the little fights over I tell her to watch what she says more often and I won't get as mad, it's about thinking before you speak. But then I was never afraid of my parents to feel I should back down and take that sort of thing.
Honestly I have no idea what to do about mom's like this. Mom's can be highly sensitive about femininity, especially if they feel like the only one. If you're really bothered but don't want to come out, say it sounds like sexism to you, or just walk away. Some parents eventually stop when they realize you're just going to walk away every time or get annoyed, others like mine, continue to do it after a few short days in between.
It's possible she may take it like that, possible she'll be the opposite or somewhere in between. That's the worst part about coming out, never knowing, no matter how liberal or how conservative a parent is, you have to expect the worst or be surprised by the best.
Anyways good luck with all that. Just thought I'd add my own two cents that didn't really make a difference to the entire situation now that I look at it....