Why was I interested in this book?

I wanted to read this book because it was sugested to me by a friend. She said she couldn't stop reading it and read it almost 4 times. Also just by looking at the cover I was interested, how it was a good reads choice award for favorite book as well as the futeristic looking setting. Another thing that grabbed my attention was the back cover saying " One choice decides your friends. One choice defines your beliefs. One choice determines yuor loyalties-forever."This made me want to read about what that choice was. And also why it determines the rest of your life. Why couldn't you just change it like you change jobs in modern society? Also the reviews on it were very good. I thought it would make a good book for this trimester.