I totally agree with sfa. Your opinion matters more to her than her classmates' and their parents' opinion. How you react to anyone's negative comments--if any--might provide you with an opportunity to show her how to shrug such things off

When I was about your daughter's age, I wore nothing other than a cowboy outfit. Everywhere. My mom never made an issue of it, and I eventually grew out of it. If anyone teased me, I don't remember it.