Only able to talk to girls I don't like

With women (and people in general, I guess) who I don't really like, I find I can speak freely and tend to make a pretty good impression. It's like my brain realizes I have nothing to lose if they don't like me, so have no problem being myself. But when I'm talking to someone I like, I start to censor myself - often to the point of looking like a stiff dumbass.

Does everyone do this too? Is it normal? Or do I have issues?