Crebassa grew up in Agde, where her parents encouraged her interest in music, starting with piano and continuing when she was 14 with singing. She continued her music education at the music conservatory in Sète. At the conservatory in Montpellier, she studied musicology, voice and piano. Whilst at Montpellier, in 2008, she appeared in the Montpellier Opera production of Manfred, which at the instigation of the director René Koering was followed by concerts around the region. She attained greater recognition with a concert performance as Isabella Linton in a Festival de Radio France presentation, in Montpellier, of Bernard Herrmann's opera Wuthering Heights, in which she also impressed the critics by playing the piano on stage.