And yesterday, she was back at the Capitol, fighting a GOP effort to repeal the very law she'd helped pass.
The bill to repeal the law was sponsored by Senator George Rivera, a Republican from Pueblo who came into office last year after Senator Angela Giron was recalled in the wake of her support for stricter gun control laws.
Senate Bill 94, which was co-sponsored by sixteen other state senators, proposed to "repeal the requirement that before any person who is not a licensed gun dealer transfers possession of a firearm to a transferee, he or she shall require that a criminal background check be conducted of the transferee and obtain approval of the transfer from the Colorado Bureau of Investigation." The bill also proposed to repeal the fee for the background check.
"It doesn't really make sense," Karina says of the proposal. When she heard about the bill and was asked to testify against it, she didn't hesitate. "I feel like if my testimony would make a difference, I'm willing to speak out as many times as I need to," she says.
After many hours of debate on Monday, lawmakers in the Senate State, Veterans and Military Affairs Committee killed the bill on a three-to-two party-line vote.
More from our Follow That Story archive: "Karina Vargas: How to donate to a fund set up for teenager paralyzed in drive-by shooting."