Cabell was born in Panorama City, California. Her grandfather, Luther Lanier, was the first African American Chief in the Sheriff's Department in Los Angeles. She is of African American, Korean and Caucasian ancestry, and was brought up in the California beach town of Ventura. As a child, she did not listen to classical music, but she did play the flute in her junior high school band. She and a classmate used to play basketball together and would "imitate opera singers". Her mother encouraged her to join the school choir and she tried out for a school musical and was a success.