What's the name of that one book?

Now it's going to be a little vague because I read the book a couple of years ago. I just can't remember the name and it's driving me crazy.

The story is told through first person. It's about a boy who's inlove with a classmate but he can never really get close to her about 3/4ths of the way to the end. One night she and the main character end up making out and he obviously enjoys it, she ends it with "to be continued" and leaves for a bit to answer her phone, she then comes back freaking out and leaves again. The next day or so the the kid and his friend wonder what happened to her and they get an announcement from the principle that the girl had died in a car accident the night she had left.

Later on in the end, he finds out the reason why she freaked out because it was the anniversary of her mother's death and she had forgotten to pick a flower to put on her grave. She died getting to the cemetary.

I know I can't be any more discrete, if I could remember any of the character names I'd have the book figured out. Anyways, I think the authors name was Tom Green or something, I can't remember.

Does anyone else know what I'm talking about?