Being a once-in-a-generation mind isn't always easy for young Sheldon Cooper. The gifted but naive preteen faces major milestones in Season Four. With college in sight, Sheldon is determined to leave the training wheels behind. But what happens when his new philosophy teacher sends him into an existential crisis? Sheldon isn't the only Cooper facing big changes. Twin sister Missy enters middle school and a new stage of womanhood, while