I'm going to be very honest - I finished this book last night, and I still have no idea how I feel about it. The first two-thirds of the book, I was absolutely ready to give it 5 stars. Beneath is beautifully written. The prose sings, and the story of a small town snake preacher enthralled with a 16 year old girl felt like something I shouldn't be reading. It was creepy and lovely. 
Somewhere around the last third of the book, the narrative bogs down hard, the focus shifts, and it lost me a bit. The ending of the story was good, but I just didn't love it anymore. So I guess I'm going to give it 4 stars, because it's just so insidious and creepy and quite good for a first novel. I definitely plan on reading more by the author.