The alleged crime took place at a picnic spot near Puddle Alley in Mosgiel, and the woman said she received a surprising request on the way home.
"He said 'do you want to date me?' And I was like 'no, what you just did to me was horrible'. He said 'I'm sorry, it's because I like you','' the complainant told the court.
"I liked you so I raped you? Who the hell says that?''
Keen had met the teen in April last year, Crown prosecutor Robin Bates said, just weeks before the incident.
He and two others were cruising in a Subaru on the night in question. Keen was driving while the passengers drank alcohol.
He dropped the two others off, before taking the teenager to a secluded area.
The woman said Keen reclined her seat and got on top of her before pulling off her trousers, ripping them in the process.
"I was holding them up but he managed to get them off,'' she said.
The complainant told the jury she repeatedly told Keen to stop and began screaming for help.
He allegedly covered her mouth with his hand to stifle the noise.
"All I can remember was asking him if he was going to kill me because that's what I thought was happening. I thought I was about to die,'' she said.
"And quite frankly, I wish I did.''
Eventually Keen dropped her off at her father's house where the teen was "hysterical'' and police were called.
Defence counsel Anne Stevens QC said there was no dispute the pair had intercourse.
She said the complainant's claims were untrue and, in fact, it had been she who had set up the meeting that night.
Mrs Stevens took the woman through pages of Facebook messages between the pair.
Three days before the alleged rape, the teen asked Keen for "cuddles''.
"I suggest it means far more than a hug,'' the lawyer said.
"There's a difference in my opinion between cuddles and sex - a huge difference,'' the woman responded.
The court heard of messages littered with kisses and love hearts.
Keen called the complainant "beautiful'', while she said she would not object to him kissing her.
"You were setting up a meeting with him to have sex,'' Mrs Stevens said.
"I wanted to drink. I didn't want to be raped,'' the woman said.
"You don't know what happened that night. You weren't there.''
The trial, before Judge Michael Crosbie and a jury of seven men and five women, is scheduled to run for four days.
