Mary-Grace Lorayne High {15} is the youngest sibling of Clarissa High. She is a spunky 15-going-on-21 year old girl. As a sophomore, she just started dating a football-playing senior boy. She has a big group of friends and they love to hang out with each other as often as they can. Like her older sister, Mary-Grace is sarcastic, quick-witted, and fiercely loyal. However, Clarissa is often disappointed in the way her younger sister, Mary-Grace, runs with the "popular kids" and she wishes she would think about more than appearances. Deep down, Mary-Grace is compassionate and loving, she cares about people. She even volunteers at a nursing home where she plays bingo with residents every Monday evening.