They told me I couldn’t write this book. I said, “I can’t not write this book.”

Writing a book means living with its contents for years. I started writing AfterMath, a middle grade novel about seventh graders dealing with loss, grief, and the aftermath of trauma caused by a school shooting, in 2015, the year my second child was born. He’s now six, and I’ve been living with the contents of this book in many forms all that time.

It’s not as if these fears—that my children or someone we love could be affected by our country’s gun-violence epidemic—weren’t in my mind before I wrote the book. If anything, I’ve grown less scared, less small. I’ve talked to so many parents who are thankful to know they’re not the only ones worried about the things I wrote about.

There were some agents and editors who didn’t want to take on AfterMath because they didn’t want to live with the subjects for the many years they knew it would take for the book to come to be. I get it. Dozens of people have asked me if I wished I had written something “easier.” Something that wasn’t so sad. Sometimes I do wish I could have. I am sure the parents of children killed in school shootings or other senseless acts of gun violence wish that they, too, could think about something easier, but they were never given that choice.

But for me, writing something more light and “fun” would have required the world to be less sad, or me to be less anxious. And until either of those things comes to be, I will likely continue to write into my fears. I will keep listening to that voice in my head that I know now is a call to action. I will honor the things that scare me, because I know they are the things that matter.

After many years of freelance writing and a few novels I stuck in drawers, I wrote the first draft of what would become AfterMath in three frantic weeks while my infant son and toddler daughter napped. But the story must have been percolating in my brain for years, given how easily it flowed out.

It’s possible I started developing the concept more than 20 years ago, when I heard about the shooting at Columbine High School in Colorado. Maybe that early seed was fed by the horrors of the Sandy Hook shooting in Connecticut. And likely, part of the idea was woven into my very DNA—my grandfather wrote in favor of gun control for the Washington Post in the 1960s and ’70s, and, while he died before I was born, the legacy of his activism bloomed in me.

But the event that felt like the final tipping point was a shooting in San Bernardino, Calif., in 2015 that killed 14 people. I wrote that first draft of AfterMath as if in a fever dream, worrying about my children and every child in our country who could not be guaranteed safety from gun violence.

“You can’t write that book,” people told me.

“I can’t not write it,” I said.

I sent it to my agent, and editors weighed in. “Rewrite it for YA,” they said.

“Middle schoolers aren’t really thinking about school shootings,” one editor told us. At that point, my older child was in kindergarten, and I knew that she and her classmates endured active-shooter drills on a regular basis, as did every other kid in New York City’s public schools. One publisher made an offer contingent on my changing the school shooting to a hurricane. I said no.

I can’t not write this book.

Margery Stoneman Douglas High School in Parkland, Fla., happened. The Santa Fe High School shooting happened. The Tree of Life Synagogue shooting happened. My agent sent the book out again—we hoped that maybe the world was ready to see that kids needed to talk about school shootings, even kids as young as middle grade readers. Especially kids that young.

We sold the book to Amy Fitzgerald at Lerner/Carolrhoda, because she understood that I wrote the book purposefully from an outsider’s perspective—the main character, Lucy, is new to a school where her classmates survived a shooting four years earlier—because many of us are outsiders to the trauma and grief of mass shootings and gun violence. But we’re all aware of it, even middle schoolers. Especially middle schoolers.

I always intended AfterMath to be read by families or with teachers, not just handed to a 12-year-old with a “good luck, buddy” and a wave. I’m not sorry it took so long for the book to find its moment. I’m just sorry it’s still so relevant.

Emily Barth Isler is a former child actor who lives in L.A. and writes about eco-friendly beauty and skincare. She has also written web sitcoms, parenting columns, and personal essays. Aftermath is her debut novel.