Peden and the victim became close and by the time she reached her teens the pair were texting. One night in February last year, Peden drove around to her house and took her back to his house where they had sex.
He again went back to her house in November of that year and took her to an isolated spot where they again had sex.
The pair were caught out when the victim's sister saw her climbing in through a window into the family home afterwards.
The victim's family had already expressed concern that the pair were getting too close and it was something that Peden was aware of, the judge said.
When interviewed by police, the victim gave a full account of what happened and said she was confused and shaken by what occurred and saw Peden as a big brother.
"She considered that you were like a best friend and she didn't have any friends at the time and you were a good person to talk to," the judge said.
Crown prosecutor Trelise Needham said although Peden had attended a restorative justice conference with the victim and her family, they were left disappointed.
"It hasn't had the restorative effect which one might hope for," she said.
But Peden's lawyer Lyn Walkington disputed her client held a position of responsibility at the church and said her client mistakenly described himself as a "mentor" during the RJ process. She described him more as a "volunteer" who was not actively involved in the church at the time.
"I feel that this issue has been taken out of context ... was he a mentor? What's an adult youth leader, your honour? He was a volunteer at camps and didn't hold himself out as a leader at camps."
She said he was very remorseful for what happened and the impact it had on the victim.
Walkington felt the RJ conference was a success.
"It really does reflect a sincere young man who has tried to set out and take responsibility for what he has done. It was a process that he felt he needed and wanted to go through."
She said Peden was a young man who had not only disrespected himself, but also his family and those who knew him at church.
"So it's been a big fall from grace for him."
Judge Spear said the court needed to consider the age disparity, the number of times the sexual acts occurred, whether there was a breach of trust, any violence or whether any predatory or grooming actions were involved.
"I do not categorise this offending as predatory nor that you groomed her. I consider you far too naive for that ... I see this offending as more as a weakness on your part in that you took advantage of a very close relationship with a young girl and unfortunately she has been the one left damaged.
"This is not a case of an old man forcing himself on a very young girl [but there is] the need for us to deter adults from having sexual interest in young girls."