My character is 17 in 1943. She witnesses something horrible (and supernatural) and flees from regional NSW to Sydney, and decides to join a religious order as a Sister (so she can participate in the community). She is the daughter of Irish Catholic Immigrant parents. Her birth name is Rose Martyn, but she introduces herself as Rose Kearney, because she is in hiding.
I know that pre-Vatican II, Sisters were given an ordination name when they joined a Order. I think that the Sisters of St Joseph is the best fit for her. What would her religious name be? Is it reasonable that it be Brigid (after the Irish Saint?) She's a fairly minor character speaking to my protagonist in 2012, so would her name appear odd to a lapsed catholic post Vatican II?
I heard somewhere that in the 1940s Sisters took male religious names, but I haven't been able to confirm this, so am completely lost.