Nenette was born on the island of Saint Pierre et Miquelon, a French overseas territory located in the Atlantic coast of Canada. Her father Emmanuel Victor Pepin was French, and her mother Henriette Fitzpatrick was Canadian of Irish origin. She was known by her family as Nenette, diminutive of Antonietta. While still a child during the First World War, she moved to France with her parents and her older sister, Jeanne Henriette. In 1926 Jeanne finished school and travelled with a dance company to Buenos Aires, where she met her first husband. Two years later, once Nenette finished school, Jeanne invited her and her father to come out to Argentina. The two settled in Villa Ballester in Buenos Aires in 1928. Nenette entered the National Music Conservatory, where she studied piano under Juan José Castro, Pascual de Rogatis and Isabel Aretz. She toured Argentina on numerous occasions, performing classical music on the piano. In 1942, after a concert she gave in Tucumán, the organizers took her to hear folk music from northern Argentina played by Argentine singer Atahualpa Yupanqui. The two became friends, and four years later, in 1946, they moved in together.