What do you think about this idea for a book?

I'm thinking that it would be about a girl in high school, who falls in love with a boy and plans on spending her life with him. But one day he breaks up with her and she basically just tries to move on. It will revolve around on what she has learned, what she does to get over him, and learn to love herself and be happy on her own.

Please don't be so harsh. It's just an idea. And if you would like to add on to it please be welcome!