Katniss had to make a choice kill President Snow or Alma Coin. They're both horrible but, Snow was outright horrible where coin pretended to be on the good guys team when underneath she is a witch.
Voting on the future of new Panam, wether or not to have the hunger games just for the game makers kids, having them suffer for their ancestors. Our heroine was in favor only because she has a plan up her sleeve.
Katniss slowly walked to the front so everyone could view the Mocking Jay, where Coin had a microphone given her new panel speech and snow was tied up in an execution style.
It's now or never she thought as she took aim and drew the arrow back piercing Alma Coin. The audience was confused and angry so they all rushed passed the mocking jay and took turns beating the president like a piñata. Plutarch Heavens bee was expecting her to make the move she did, he wasn't surprised.
Peeta and Katniss had two little kids. Annie was a single mother and decided to not marry anyone else after Finnicks death because nobody else can make her feel the way he can.