This report contains explicit descriptions of sexual abuse.

(CNN) Kyle Stephens said she had her first sexual experience when she was 6 years old.

Larry Nassar, a family friend, exposed himself to her in a dark boiler room. From then until she was 12 years old, he would pleasure himself in front of her, rub his penis on her bare feet and put his finger in her vagina.

At 12, she told her parents about the abuse, but they didn't believe her. The abuse -- and their denial -- left her feeling brainwashed, caused a split in her family relationship and led to crippling anxiety, she said.

But on Tuesday, Stephens defiantly stared down Nassar in a Michigan courtroom to inform him that the abuse was over, and his time as a free man was up.

"Little girls don't stay little forever," Stephens said. "They grow into strong women that return to destroy your world."

Stephens was the first victim to speak in what is expected to be days of victim impact testimony as part of Nassar's criminal sentencing.

Given the remarkable scope of the years of abuse, several days of court have been set aside for victims or their parents to speak out about Nassar -- and the systems of power that protected him. Prosecutors in court said that 98 victim statements are expected in all, though that number could change.

Nassar, the former USA Gymnastics team doctor for about two decades, pleaded guilty in November to seven counts of criminal sexual conduct in Ingham County in Michigan. As part of his plea deal, he admitted that he used his position as a trusted medical professional to sexually abuse young girls.

He also pleaded guilty to three other criminal counts in Eaton County. And he has already been sentenced to 60 years in prison for child pornography charges.

'It all started with him'

Stephens said Nassar was a "repulsive liar" who had convinced her family that she was the one lying.

"Sexual abuse is so much more than a disturbing physical act. It changes the trajectory of a victim's life, and that is something that nobody has the right to do," Stephens said.

Kyle Stephens said her abuse began when she was 6 years old.

On the witness stand, Nassar kept his head down and his eyes closed, and covered his face with his hands for much of the proceedings. He occasionally used a tissue to wipe away tears.

Many of the victims first came into contact with Nassar to receive treatment for injuries, particularly from gymnastics or other sports. They were young and naive, the women said. He was a medical professional, and a widely revered one at that, and he used that to his advantage.

Jennifer Rood-Bedford said she played volleyball at Michigan State and went to Nassar for shoulder, back and leg injuries. In a private room, he laid her face down on a medical table and began applying pressure with his fingers to her pelvic area, saying it was part of his medical treatment.

"He would just ask me questions and talk about life, his work, and how he had used this method to help so many," she said, and he gradually put his fingers in her vagina. "I remember laying there wondering, 'Is this OK? This doesn't seem right.' I didn't know what to do."

Rebecca Mark said she was a freshman on the JV soccer team in 1999 when she went to him for treatment.

"He molested me, she said. "He molested me while my mom was in the room."

Larry Nassar rests his head on his hands Tuesday during his sentencing for seven counts of criminal sexual conduct.

A number of victims said they suffered from self-doubt, anxiety, depression and post-traumatic stress disorder. Some said they or their loved ones harmed themselves because of Nassar's abuse.

Stephens said her father committed suicide in 2016. She said she believes it stemmed from the shame and self-loathing her father felt when he realized that she was telling the truth about Nassar.

Donna Markham, speaking in court, said she took her 12-year-old daughter Chelsey to Nassar for medical treatment years ago. On their drive home, Chelsey broke into tears, saying he put his ungloved fingers in her vagina even as her mother was in the room.

The incident set Chelsey on a path toward depression and drugs, Markham said. She took her own life in 2009 at the age of 23.

"Every day I miss her. Every day. And it all started with him. It all started with him, and it just became worse as the years went by until she just couldn't deal with it anymore," Markham said.

Several of the victims placed blame on USA Gymnastics and Michigan State University, which employed Nassar for years as the sexual abuse occurred. Both institutions have denied that they ignored the accusations against the doctor and say they took action when they learned about the abuse.

Olivia Cowan said she used to sleep soundly before Nassar's abuse but now spends more nights than not crying, filled with anxiety that leaves her exhausted, unable to sleep and unable to trust people.

"Today, I am a mother, a wife, a daughter, a friend that is struggling each day to find peace and joy in all the things that once made me happy," she said.

Cowan said USA Gymnastics and MSU ignored complaints of wrongdoing about Nassar and have still refused to take responsibility for their role in the abuse.

"You failed all of us," she said, addressing USA Gymnastics and the university, "and for that I see you in the same category of criminal as I do the criminal standing before us today."

'No. It was not my fault.'

As a doctor for USA Gymnastics through four Olympic Games, Nassar treated hopeful young gymnasts and world champions alike. His victims include some of the most famous gymnasts in American history, including several members of the 2012 and 2016 gold medal-winning teams.

Aly Raisman, Gabby Douglas and McKayla Maroney have said previously they were abused by Nassar. Simone Biles , who set an American record with four gold medals in women's gymnastics in 2016, said on Monday that she, too, was a victim.

"For far too long I've asked myself 'Was I too naive? Was it my fault?' I now know the answer to those questions. No. No. It was not my fault. No, I will not and should not carry the guilt that belongs to Larry Nassar, USAG, and others," Biles, now 20, said.

It's not clear who will be present at the victim impact hearings. Aly Raisman said on Twitter that she will not attend "because it is too traumatic," but her impact statement will be read in court.

Nassar also worked at Michigan State University from 1997 to 2016 as an associate professor, and he served as the gymnastics and women's crew team physician.

Under the guise of providing medically necessary treatment, Nassar instead abused many of his patients. He admitted in court to putting his finger into the vagina of patients in cases going back as far as 1998 -- including girls under the age of 13.

Attorney John Manly, who represents more than 100 victims in civil lawsuits, has argued that Nassar was supported in his abuse by institutions like USA Gymnastics.

Facing accusations of a cover-up , USA Gymnastics said in a statement that it acted appropriately and informed law enforcement when it learned about the abuse in 2015.

"We are sorry that any athlete has been harmed during her or his gymnastics career. USA Gymnastics is focused every day on creating a culture of empowerment that encourages our athletes to speak up about abuse and other difficult topics," the statement said.

Patrick Fitzgerald, the lead attorney for Michigan State University in these cases, defended MSU's response to Nassar in a letter to the Michigan attorney general.

"The evidence will show that no MSU official believed that Nassar committed sexual abuse prior to newspaper reports in the summer of 2016," he wrote, according to the university.

Michigan State President Lou Anna Simon and Board of Trustee Chairperson Brian Breslin chose not to attend the sentencing this week to keep the focus on getting justice for the victims, MSU spokesman Jason Cody said.

"They are truly sorry for the abuse these victims suffered and want to hear these brave women as they make their voices heard," he said. "Both the president and Trustee Breslin are viewing the sentencing hearing though live media streaming."