Darlene Wilkins is a character in Young Sheldon and is portrayed by Julia Pace Mitchell.
She was introduced as a teacher when she went on a trip with her husband. (A Musty Crypt and a Stick to Pee On)
One day, Missy tells her about the accident her grandmother and brother got into that damaged their car. She let Missy skip the test; she told her to not push her luck when she asked about homework. (The Geezer Bus and a New Model for Education)
It's known later on that she cheated on Wayne with his best friend and is currently pregnant with his baby, and not Wayne's. At work, Missy is soon to be taking a test in Darlene's class. Before the test taking is about to start, Missy continuously asks questions regarding her affair. Much to her embarrassment and fury, Darlene angrily calls her ex-husband demanding him to tell her more about what he told Missy earlier. (An Ugly Car, an Affair and Some Kickass Football)
Darlene taught class and gave an exam. She told Billy and Missy to not talk to each other nor cheat. She was told to not badger them about cheating since she has her own personal issues to deal with. She calls her parents about it. (Teen Angst and a Smart-Boy Walk of Shame)