I don't mean to seem rude, but I feel the need to be very frank here. Hunger Games has been overdone on this site. There are numerous story-games based off of the books. I would not recommend this for your first story-game. However, if you are intent on doing it, you might try to find an experienced user who enjoys and has extensive knowledge of The Hunger Games and ask them to be a co-author.
Okay, now, as far as the story, I would have to say that "fifth" is a little early. I haven't read the books, but I know that would be only five years after the districts rebelled against the capital. So, the revolution would still be on everyone's minds and the reaping would probably be a whole lot...rougher. Also, remember that the books are dystopian in nature, meaning that even if you win, you don't win.
Again, if I were you, I would hold off on making such a monumental, labor intensive, hard to pull off game until I had a little more experience. You might try writing a basic story-game or two first.