Continuity mistake: Near the end, when Betsy and Arlene are cutting the stars out of the American flag, one shot is a close up of their hands - they have almost finished when the camera cuts to a wider shot as they question the legality of the activity. When they resume cutting their scissors are further back then they were in the close up ie. they are cutting where they have supposedly already cut.
Factual error: When Michelle Williams gets contact lenses, they zoom in on the eye as she's trying to put the contact in. It's obviously a soft contact lens since you plainly see it folding over. They didn't have soft contact lenses back then.