The Other Sister (1999)

Twenty-four year old Carla Tate is a slightly mentally challenged young woman who, after years of special education at a private boarding school, has successfully transcended many of her limitations--except for that of her over-protective mother, Elizabeth. When Carla graduates and returns home with dreams and ambitions, her need for personal fulfillment begins to express itself in ways her mother is unable to accept. When she falls in love for the first time, Carla defies her mother in order to prove that despite all appearances she has the capacity to be a responsible adult, worthy of love and being loved. Embarking on a journey of self-discovery, Carla and her boyfriend Danny set out together to find answers to some of life's toughest challenges, and prove that sometimes, an ordinary life can be an extraordinary achievement.