Yes, it is absolutely possible to experience delayed processing of a traumatic event like a shooting. What you're describing aligns with symptoms of Post-Traumatic Stress Disorder (PTSD), which can emerge months or even years after the initial event. The brain often suppresses or dulls reactions to trauma to help you function, but over time, when the mind perceives it as "safe" to process, symptoms can surface as recurring nightmares, intrusive thoughts, hypervigilance, anxiety, or avoidance of situations related to the event. This delayed reaction is completely normal and widely recognized in psychology, and many people have experienced similar delayed responses.