The priest, who is in his early 30s, told a court he didn't realize he was breaking the law when he had a sexual relationship with the girl, whom he called "the love of my life."
"I did not know that the age of consent was 16 years old in Norway. In my home country of Germany it is 14 years old," the priest said.
The girl asked the court not to convict the priest because she said the relationship was consensual, TheLocal.no reported Wednesday.
She said the relationship was discovered when she made a confession at St. Paul Church of Bergen that she believed to be confidential.
Alois Broderson, pastor of the church, said the confession was not deemed confidential because the girl wasn't a confirmed Catholic.
If convicted, the priest faces six months in jail, one of them suspended, TheLocal.no said.