She never reported the attack. A friend who was sexually assaulted around that time was expelled from the private school after an Honor Code review, Parker-Phillpotts said.
Coleman and Parker-Phillpotts were among 40 protesters unhappy Wednesday with the Provo school's handling of sexual assault cases.
Some joined Coleman wearing armbands, while others held signs that read "end rape culture" and "BYU: Protect victims, don't shame them."
The protesters walked onto campus to deliver a petition with the signatures of more than 90,000 people who say the school should amend its Honor Code policies with an amnesty clause protecting victims of sexual assault.
President Kevin Worthen was not available, but Academic Vice President Brent Webb said he would make sure he saw it.
"We welcome you here, and we thank you for your concern," Webb said.
BYU this week said it is considering changes and will review the relationship between its Title IX department — federally charged with ensuring students don't face sex discrimination — and its Honor Code Office.
In a video statement released earlier Wednesday, Worthen described what he hopes that process yields.
"I hope we have a system that people feel they can trust, particularly again the victims of sexual assault. And that we have one that creates an environment in which we minimize the number of sexual assaults."
The online petition was started last week by Madi Barney, who said the private school launched an Honor Code investigation into her conduct after acquiring records related to her sexual assault, which she reported to Provo police.
BYU's Honor Code forbids students from drinking, using drugs, wearing form-fitting clothing or engaging in premarital sex. Students who do not meet the conduct standards may be expelled from school.
Before leading the walk onto campus, organizer Kelsey Bourgeois, with online petition site Care2, asked who in the crowd has experienced victim-shaming or blaming. About 20 people raised their hands — including Coleman.
Coleman, who is from Provo, was 16 when, she said, a blind date with a BYU student got out of hand. She never went to police for fear her parents would find out.