I was going to jump in and defend what is quite possibly my favorite Pratchett book, but SunshineDaydream said it much better... As for her refusal to "accept being a girl," say rather that she "doesn't want to accept a girl's place in Borogravia." It's because women can't hold property that she goes looking for her brother; she doesn't want The Duchess to fall out of her family's hands if she can help it.