She went to college at the same place as miller, which is reed college, and after her freshman year she decided to study at a school in france. While there she was introduced to another student from Reed who she was very fond of and her name is Nadine. Nadine was a very nice person to Penny and listened to Penny’s childhood problems intently and with care. One night Nadine told Penny that she was a christian and Penny was very upset by it.
She did not want to believe that this person that was so nice, kind and listened to her so well was a Christian because from her perspective of Christianity these were not traits of a Christian. Then when Penny started to think about it she found out that maybe Christianity has something to offer her. This was the beginning process of her conversion. She may not have changed her ways immediately but this way of thinking and meeting Nadine really opened up her mind to Christianity.
Later in the book it goes to talk about how she converts after hearing the voice of God while she was high on drugs. This may or may not be true but personally I believe that it is. I think that God will come to people when they are most vulnerable and tell them straight up what they need to here. A couple of days later after hearing Gods voice she prayed and asked for forgiveness of her sins and that is the day that she converted. All that was left was a public display of conversion, also known as baptism.