At the age of 13, Phillips returned to the United States with her father and sister, settling again in Los Angeles. There, she became a childhood friend of Sue Lyon. Phillips attended several high schools in Los Angeles, including Alexander Hamilton High School and Marshall High School. While a student, Phillips played several sports and studied piano, guitar, and cello. During her sophomore year, after being caught skipping classes and subsequently forging absence permission slips, Phillips was expelled from Marshall High School and transferred to Eagle Rock High School.