Sean Graves will always carry some of Columbine with him.

Shot several times in the massacre’s first moments, Graves spent three years after the tragedy in a wheelchair.

In 2002, he rolled onto the graduation stage, stood up, took his diploma and walked away.

Graves still struggles to run or climb a ladder without strain.

“I was 15 when I was shot,” Graves said. “That was 20 years ago. I’ve lived with these injuries longer than I lived without them.”

Graves still struggles with flashbacks and post-traumatic stress, he said. To this day, he analyzes any room he’s in for exits and people who could be threats.

The years after the tragedy brought darkness and anger, Graves said.

“I couldn’t tell you why it happened,” Graves said. “I wasn’t in the killers’ shoes. But for me, the only way I could move forward without being angry at life or my situation was to forgive them.”

“It was relieving, to be honest. Once I realized I didn’t have to spend the rest of my life angry at this pair of people, a weight was taken off my chest. I stepped out of the darkness.”

Graves’ wife, Kara, said she is grateful for her husband’s personal growth.

“Without forgiving them, it’s like they won,” Kara said. “They still control your life. We’ve been together 16 years, so I’ve seen him before and after he came to terms with it. It’s definitely improved our quality of life.”

Among the more profound impacts, Kara said, is how they raise their 3-year-old daughter.

“I think 20 years ago this wasn’t at the forefront of anybody’s mind,” Kara said. “Today it’s a way of life. As kids we did tornado drills. Our daughter will do shooter drills. It’s taken our innocence away.”

Graves said if there’s a silver lining, it’s that his daughter will grow up more aware.

“I kept telling myself it wasn’t real,” he said. “I hope my daughter is smarter. I’ll tell her: If this happens, you have to survive.”