Who is Coira in the book, J: A Novel?

Coira is the daughter of Rebecca and the mother of Ailinn. Lovingly raised by the nuns of Saint Brigid’s Roman Catholic Convent and Orphanage, Coira is happy until she is sixteen when she learns the truth of her past and her lineage. Coira goes out into the world, becomes pregnant with Ailinn, and returns Ailinn to the nuns to be raised. Coira is never heard from again.