What would you ladies do?

So my boyfriend told me her mother hates women in trousers and he doesn't want her to hate me for no apparent reason. so when we go to see her I should never Wear trousers.i thought for a moment and that's like hiding who I am. He doesn't have problems with what I wear but his old mom does. He said she is old and so nothing much can change about her attitude. I can wear trousers like a whole month or two everyday.definitely they are big part of my life. I'm not saying I will wear them on my first day of meeting her. But for as long as I'm around there I shouldn't.

So what will you ladies do if you were in my shoes?pretend you don't wear them to please her or be yourself and risk a cold reception?