Im going to a cowboys and indians party..what should i wear?

right off the bat i wanted to be an indian...because the girls were going to be indians and the boys cowboys....but now its all mixed in together and id still like to be a native american....i know howd id wear my hair..and i have shoes for it...but outfit wise? i dont even know! but if i should be a cowgirl....lemme know. the party is saturday!