premise of being a jew *spoiler?*

Only watched the trailer, so bear with me.
She finds out an ancestor was a Jew; so this does not make her a Jew.
It is not a race; it's a religion.
She's been a practicing Roman Catholic all her life, and ready to take vows as a nun; she's a Polish Catholic.
And, I'm not making any other point here, nor casting aspersions about Poles, Catholics, or Jews.