Colorado's new gun control law raises the age of legal gun purchase to 21 yrs of age.
In my thinking, the United States government cannot legally enlist anyone under the age of 21 then. "change my mind"
Senate Bill 23-169 raises the age to purchase any gun to 21 years old. Previously, the age restriction was 18 to buy a long gun and 21 to buy a handgun. There are exceptions for members of law enforcement and the military.