"It took me years to be able to talk about it and now that I can talk about it, it's still like pouring salt in old wounds," Lindholm said.
In April 1999 she was a sophomore, an "A" student, a cheerleader, cowering in her classroom, watching teacher Dave Sanders die.
She dropped out of school, flunked out of college. Now she's fighting back, studying to become a doctor.
"It's very hard, because part of my day-to-day life is school and school is my one phobia now," she said. "It's the one place I'm really scared to be."
Eric Harris and Dylan Klebold killed 13 people plus themselves at Columbine. Frank DeAngelis was principal then and still is today.
"There's kids out there and saying, 'look, I'm a nobody,'" DeAngelis said.
When Seung-hui Cho calls the Columbine killers "martyrs" in his manifesto — DeAngelis worries the wrong lessons were learned.
"There's so many people that idolize Klebold and Harris, and that scares me," he said.
It also scares Tom Mauser. He wears the shoes his son Daniel was wearing when he was killed at Columbine.
"It's something I do to really represent the fact that I'm walking in his shoes to honor him," Mauser said.
He says Columbine taught him guns are too readily available. Now he crusades for gun control in Daniel's name.
"Tragic as what happened in Virginia is, the fact is we lose more than two times that number of people to gunshots every day in this country," Mauser said.
Brooks Brown, once friends with Harris and Klebold, says the lesson of Columbine is simple: spot and treat troubled youths.
"They actually share all the same red flags," Brown told Whitaker. "The run-ins with the police, the violent writing, the threats on other students, the dark behavior. All of that screams. The real signs are that these kids feel hopeless – they are angry as hell."
A memorial is being raised in Littleton, Colo., for the lives lost eight years ago, a symbol of hope this won't happen again.
"I want to hope and in my brain I have hope, but I haven't seen a damn reason for me to have it," Brown said.
Perhaps this time the lesson will stick.