Almost Famous

In 1969, child prodigy William Miller struggles to fit in with the world. His widowed mother Elaine has led him to believe he is 13 years old, until William's older sister, Anita, tells their mother to tell the truth. His age is actually 11; his mother had him start first grade at 5 years old and then he skipped fifth grade. Their mother strictly controls and protects him and Anita, forbidding rock music and other unwelcome influences, driving Anita to leave home and become a flight attendant. Read more on Wikipedia.