The Marshall Project is a nonprofit newsroom covering the U.S. criminal justice system. Sign up for our newsletters to receive all of our stories and analysis. Last month’s mass shooting at a high school in Parkland, Florida, reignited debate over gun control in the United States with a special focus on the legal minimum age for gun ownership. Many on both sides of the aisle have argued that our laws currently put guns in the hands of young people who lack the emotional maturity to use them responsibly. Having spent the last 22 years in prison for shooting a man to death when I was 20 years old, I’d have to say I agree. This commentary was published in collaboration with Splinter. Under federal law, the minimum age to buy a handgun from a licensed dealer is 21 years old. It drops, however, to 18 if the gun is purchased from a private seller. Further, federal law allows individuals 18 and older to legally purchase long guns like the Smith & Wesson M&P 15 .223 used by the 19-year-old Parkland shooter. Weeks after the shooting, the state of Florida enacted a law that, among other things, raised the age to buy a rifle in the state to 21 years old. President Trump responded to the tragedy by tweeting his support for comprehensive background checks, prohibiting the sale of bump stocks, and raising the age for gun ownership to 21. With the NRA opposed to such regulation, any change to federal law seems unlikely. Still, the majority of Americans surveyed support the idea. Indeed, I’ve strolled the yard of the prison where I’m incarcerated and spoken with a number of men who committed acts of gun violence in their youth. The overwhelming majority said they support raising the age for gun ownership. In fact, most—myself included—believe the age should be raised much higher than 21. In almost every conversation I had, the men mentioned how immature their thought processes were when they pulled the trigger, and how they didn’t really come into their own until their late twenties. They spoke of impulsive decisions based on little thought and, more often than not, fear. Take me for instance. I was robbed at gunpoint three times in my teens. In the third incident, I was stuck up in broad daylight by four armed men. It was then that I decided I needed a gun, so I bought one, illegally, in the parking lot of a gun show. From that day forward, I often carried a gun with me, either on my person or in my car. I thought it made me cool. I'd get drunk and show it off, or wave it around. Several times during an altercation I fired shots into the air. It wasn't long before I figured out how to purchase guns legally. Then I bought a few more handguns and even an SKS assault rifle, similar to an AK 47. Each time I purchased a new weapon, I told myself—and anyone who inquired—that I needed it for protection. But who the hell needs an assault rifle for protection? What did I think I was going to do if someone tried robbing me again at gunpoint, draw my gun and blast away? Sounds good. But in reality, that's ridiculous. I was so filled with anger back then. I had no concept of taking a deep breath and considering my options. Instead, I’d just react—usually based on some combination of fear, anger, and shame. That’s what happened the night I caught the case that landed me in prison. My victim and I got into a fight that night and he got the best of me. Instead of walking away, I reached for my gun and pointed at him. The gesture didn't solve anything but it made me feel powerful again. Then he started taunting me, saying that I didn't have the balls to shoot. All that anger and shame and fear came boiling to the surface. My common sense and human decency abandoned me. Something inside me snapped and I pulled the trigger. I kept pulling it until the gun emptied. I take full responsibility for my actions. I killed a man. Still, I can’t help but wonder what would have happened if we’d met just a few years later, if I’d been just a little more developed, if I didn’t have a gun. To be sure, research suggests that the majority of gun crimes are committed with guns obtained unlawfully. More often than not, the men and women who commit violent crimes purchase their guns from others who either stole them or bought them from the legal owners. Still, a significant number of violent crimes are committed by legal gun owners, including more than 80 percent of mass shootings. We as a nation need to do everything possible to keep guns out of the hands of people who aren’t capable of handling them responsibly. My own experience and what I’ve learned from my peers in prison suggests that should include limiting access for young people. If that means raising purchase age-limits really high, then so be it. Jerry Metcalf is incarcerated in Michigan. In addition to his published work, he volunteers as an aid to the mentally ill and trains service dogs for Paws with a Cause. He loves to read, write, and daydream.