I'd just dive right in! No one seems to notice when I wear the boy's clothes...I always try to put them back on the men's hangers so they get put in the right section, but the fitting room lady always goes "no, you a girl, you put them on girl's hook." :| So the fact that the clothes were male didn't seem to even register with her.
Besides that, it's a lot more socially acceptable for 'girls' to wear men's clothes.
