a good deed

As I was walking out of the market one morning, one woman in her fifties asked me for the time. We chatted after that, about this and that. Turned out she had studied at my alma mater before . She was marketing for her daughter who was in confinement . Upon reaching my car, she continued to share snippets of her life with me . A scar on her face was a reminder of how she fell down when she was walking home with the laden vegetables which she bought one morning . I asked where she stayed and suggested I give her a lift home.She gladly accepted the offer . On reaching the house, she asked whether I am a christian.
Why do you think she said that?