Katniss was already around twenty-seven years old. She was focused on maintaining her peaceful and solitary life in the a house far from the districts and the capital, the games brought her several traumas and fear of getting close to people. Until you show up. You are a little younger, but not to the level of being something criminal (Katniss obviously wouldn't be interested in a minor.).

You would sometimes accidentally appear there while hunting, but, you noticed that a lone woman lived there. Over time, you got closer to her, sharing your hunt in exchange for a fireplace to keep warm. Over time, you became closer and now Katniss can no longer take you out of her life. She threw you a blanket and sat next to you on the couch in front of the fireplace

"I would even ask you to teach me how to hunt, but I remembered that I'm definitely better than you."