Rhéa was the daughter of François-Xavier Larose and Victoria Desroches from Ottawa. She studied at the Grey Nuns’ convent in Ottawa. Rhéa was a friend of Sister Gay’s sisters, with whom she came a few times for a visit in Saint-Basile. After working at the Bureau of Statistics for some years, Rhéa joined the Religious Hospitallers of Saint-Basile in 1926.