I'm challenging my girlfriend's status as a person of color.
Are you ashamed of being white?
On the contrary, I want to be able to talk with white people more freely.
It is bad to lie to people about your race. You should just let people speak their mind.
How am I lying? Are you not white too?
You should let your girlfriend identify how she wants. If she's a person of color, she should be allowed to say that she is, but if not, you should encourage her not to lie about it.