Chapters 1&2

A couple of days ago, I began reading The Hunger Games by Suzanne Collins. So far the readers have been introduced to the main character- Katniss Everdeen. Katniss may be a girl, but she is by no means girly. She must be tough because she must provide her family with food, which is hard since the story takes place in a post  apocalypse setting where food must be found in the wild by hunting and gathering, and by the means of trade. Katniss's father died when she was young and her mother is somehow disabled from doing much, I assume she is depressed from her husband's death in a mine explosion. Katniss also has a younger sister name Prim who is twelve years old and much girlier than her. Her best friend and hunting partner's name is Gale.He is eighteen years old; two years older than Katniss, but they are very close.
          Every year, each district much randomly choose a boy and girl ages twelve to eighteen to compete in a death match called "The Hunger Games". This year, Katniss's sister Prim is chosen and is only twelve. Katniss volunteers herself to take her sister's place because she cannot bare to see her sister possibly killed on television(The Hunger Games are a nationally televised event). For some reason, this kind of sacrifice for a loved one doesn't usually happen and its very strange to the people watching. Why has this idea of selflessness disappeared? And how far can selflessness go in Katniss's favor?