How She Died, How I Lived by Mary Crockett
I was one of five. The five girls Kyle texted that day. The girls it could have been. Me. Lindsey Farrier. Taylor Avril. Blair Mattern. Jamie Stroud. Only Jamie--beautiful, saintly Jamie--was kind enough to respond. And it got her killed.
On the eve of Kyle's sentencing a year after Jamie's death, all the other Chosen Ones are coping in various ways, but our narrator is stuck. She's still trying to figure out why she gets to live, while Jamie is dead.
Now she finds herself drawn to Charlie, Jamie's boyfriend--knowing all the while that their relationship will always be haunted by what-ifs and why-nots. How do you go on living when you know it could have been you? Maybe should have been you?