Interesting, but honestly I don't really get why there would be a perception that "Star Wars is for Boys". I suppose I could see it to some extent (if you really push it) with the original trilogy, but even then you had things like the Ewoks and droids which even non sci-fi girls thought were cute. Heck, they even had entire spin off series for young kids like this of both genders (Droids and Ewoks). With the prequels and Lucas firing the Mechandising shotgun, I can't see how anyone would get that impression with Natalie Portman's "Queen Amidala" and the like. She's a little two young for the expanded universe such, but there are a number of female characters like Mara Jade and the like to be found there as well.
At any rate, the whole situation confuses me, and I'm glad it turned out well.
Let's just hope she develops into a healthy fangirl who looks good in a metal bikini (waaay down the road) and remembers who made fun of her enough to make them cry.
If she wasn't in first grade I'd have suggested also showing her some of the amateur cosplay sites and all of the girls who dress up as Star Wars characters for conventions and such. While most of the pictures would be fine, you never know for sure what kind of stuff your going to find (and jokes like the one above aren't for first graders).