Continuity mistake: When the girls in the red jeep pull up to the mail boxes, Tessa gets out and says "almost time for a tan and get wasted." Another girl then gets out and throws one arm up in the air and cheers. From the front shot, you see that both her sleeves are still over her shoulders, and her hair is over her left arm, which is down. From behind and the sleeve on her left shoulder is down so her arm is showing, and her hair is now behind her back, with her pink bra strap visible.
Picture added by Quantom X