Abandon by Meg Cabot

There's a lot of things that's hard to come back from. Death tops that list. After a near-death experience nearly two years ago, Pierce can't seem to get back into the swing of life. She's constantly finding herself in trouble and looking out for the mysterious (and terrifying) boy she met in the afterlife. When her mom moves them to a tiny island off the coast of Florida, they both hope they'll get a fresh start at a happier life, but it seems Pierce is destined for much more.