Stephanie Stiles is a cheerleader at the high school both Beth Ann and Merrick went, at the time of their disappearance. It is obvious that given Beth’s appearance, Stephanie didn't consider her popular, and didn't believe that Merrick would care much for her. She explained these in an interview for Mt. Pleasant Tribune.
It is most likely that Stephanie Stiles is no longer a resident of Mt. Pleasant, at the time of the game.