Courtney Eaton is teenage Lottie, who we learn in the first season has schizophrenia. Over the course of the series, Lottie frequently has premonitions whenever something bad is about to happen. For example, she had a feeling Taissa and Van's group would run into trouble when they separated from the rest of the team to look for signs of civilization. By the second season, Lottie becomes a spiritual leader in the group.
Image Source: Getty/ Steve Granitz