Fourteen students died on Feb. 14, 2018, in Parkland, Fla., inspiring marches, new laws and widespread calls to stop the onslaught of gun deaths. But in the year since one of the worst school shootings in the United States, nearly 1,200 more children have lost their lives to guns in this country.

[Read more on how America responded to Parkland]

The number alone might stop most people in their tracks. But editors at The Trace, a nonprofit news organization that reports on gun violence, wanted to remember the dead not as statistics, but as human beings with rich histories. This week they launched “Since Parkland,” a website compiling profiles of every one of the victims. To tell their stories, The Trace turned to those who could relate most closely to the victims: other young people.

That’s how Mary Claire Molloy, 18, found herself trying to sum up the life of a 9-month-old boy, Jason Garcia Perez, who — along with two of his siblings — was shot and killed in August in Clearlake, Calif., by his father, who then shot and killed himself.

Ms. Molloy, a high school senior in Indianapolis, turned to developmental milestones to try to recreate Jason’s life of crawling and learning to talk. She was one of 200 teenagers to write the profiles.