What's the Name of That Book??? discussion

I read a book a couple months ago about a girl who's parents know that some sort of disastrous event is going to occur so they send her to an unfinished nuclear shelter. Along the way she meets a girl and then two boys and brings them with her to the shelter. The book alternates between her keeping a journal of those events (I think) and the future where a group of kids are reading her journal and worshipping her as a sort of goddess. They use cheerleaders and jocks and other contemporary words like that to describe different groups of kids. I think the book may be part of a series and if so I want to find and finish the series but I'm not sure and can't remember the name in order to look it up and see. Thanks in advance for your help!!

Half Lives by Sara Grant?

Yes! Thank you so much :)

Great! Glad you found your book. :)