Both my grandmothers were very religious. My grandmother on my mothers side was Catholic and the one on my fathers was Baptist. I know they were both strong believers, but other than that I don't know much about their church related activities.
Margaret McFadden, my maternal grandmother (Ruth McFadden) had a sister who became a nun. Among the photographs in my grandmothers collection I found this photo of Margaret, who became Sr. Donata. After a little searching I found her name among the list of deceased sisters (http://ihmnew.marywood.edu/1.WhoWeAre/DeceasedSisters.html) of the Immaculate Heart of Mary in Scranton Pennsylvania.
I believe Margaret is on the right
She died in 1953 so I never knew her and don't remember her being talked about all that much so I have no idea what her life was like or why she chose such a life.