Principal was born in Fukuoka, Japan, the eldest daughter of United States Air Force sergeant Victor Principal, after whom she was named and who was then stationed in Fukuoka. Her paternal grandparents were emigrants from Italy, originally surnamed Principale. Her mother, the former Bertha Ree Veal, was born in Georgia and was of English descent. Because her father was in the US military, they moved often; she grew up in London, Puerto Rico, Florida, Massachusetts, and Georgia, among other places. She attended 17 different schools, including studying at the Royal Academy of Ballet while her family was stationed in England.