It wasn't until 1959, at the age of 38, that Chookasian made her first opera appearance, making her debut as Adalgisa in Bellini's "Norma" with the Arkansas State Opera (ASO). Edward McGuire, founder and stage director of the ASO, offered her the part after soprano Barbara Stevenson, who sang Norma, recommended her. Stevenson gave McGuire a recording of a "Messiah" that she had sung with Chookasian in Salt Lake City and, after hearing the recording, McGuire knew he wanted Chookasian to sing the part.