The Belfast woman claims she was 15 when she embarked on a sexual relationship with Mr McPeake.
The 72-year-old denies 12 counts of sex offences against her.
She made her claim during her third day in the witness box.
The abuse is alleged to have happened from summer 2009 until February 2010.
She alleged in Belfast Crown Court she became sexually involved with McPeake during a group trip to the Republic of Ireland, and that when the group returned to Belfast, her relationship with Mr McPeake progressed onto intercourse.
The woman was questioned at length about the allegations she had made against Mr McPeake.
When she was asked about an alleged pregnancy scare, the woman said she "panicked" as she was only 15 and that Mr McPeake had lost his temper when she told him.
This, and all her other claims, have been refuted by Mr McPeake, who makes the case that no sexual activity occurred between him and the then schoolgirl in 2009 and 2010.
A defence lawyer questioned the woman about her claims of sexual activity on two cross-border trips as well as alleged incidents she said occurred at the McPeake School of Music in Belfast, at another music workshop in the city and in his car.
Telling the jury it was Mr McPeake's case there was no sexual activity, the lawyer accused the woman of being a disruptive influence during one of the cross-border trips, where she made a nuisance of herself and had to be chastised by Mr McPeake for her bad behaviour.
This suggestion was rejected by the woman, who said that at that time they were in a relationship and she was in love with him.
She was also asked about comments she made about wanting to wreck his life the way he had wrecked hers, and also comments she made to Mr McPeake's son via Facebook about his father.
Breaking down in tears, the woman said she was "angry and hurt" about what Mr McPeake had done.
She said: "All I wanted was an apology, to say he was sorry and that he was wrong. I just wanted an apology from him."
When she was accused by the defence lawyer of making false allegations about Mr McPeake, she answered: "They are not false, they are true."
And when she was told by the lawyer "I have to suggest to you there was no sexual activity between you and the defendant", she replied "there was."
The trial is due to resume on Monday.

Michael Davies, 71, had been staying at a hotel with his wife at the holiday resort when he disappeared.
The couple, from Blaina, Blaenau Gwent, had travelled to Sandown on the island by coach, Hampshire Constabulary said.
But Mr Davies, who suffers from high blood pressure, has not been seen since the early hours of Wednesday.
The force said Mr Davies wandered off after dinner at the Hotel Maria in Sandown at 21:30 BST and CCTV images later show the him less than half a mile inland from the seaside hotel.
A police spokesman said: "We are growing increasingly concerned for the welfare of a 71-year-old man.
"Having reviewed CCTV it appears that Michael was in the Avenue Road area of Sandown just before 01:00 on Wednesday morning."
Police said the pensioner's family were worried because Mr Davies relies on medication to control his blood pressure, which he would not have access to.
He is described as white, with cropped white hair, and wearing a blue tee-shirt, blue Reebok jumper, jeans and a baseball cap.
A 20-year-old woman who claims she was sexually abused by traditional Irish musician Francis McPeake has claimed in court he "lost his temper" when she told him she thought she might be pregnant.
[NEXT_CONCEPT]
A pensioner from south Wales is at the centre of a police hunt after vanishing during a coach holiday to the Isle of Wight.