What does being a girl have to do with what color you paint your room? Why not blue? Will that be beged ish or something?
If you have blue eyes will you have to get brown contact lenses?
If people tell you that you look beautiful in blue but terrible in pink, will you still wear only pink? (Well, actually, nowadays most of the girls/women I see are wearing black. Why, I don’t know. I would think that _black_ would be beged ish.)
Besides, the blue/boy and pink/girl is taken over from non-Jewish culture. Why should we even bother with it?
If you like blue, by all means paint your room that color and enjoy.