What book should i write about?

i actually want to write a book about a dream a i had. It was really vivid seemed almost real. But that dream has bin chewing on my brain till i would think of it. But im never really gonna become a writer (its not wat i aspire to do) so i will just give you little detail. I had a dream, and the 15 yr old girl was me. There was a 32 year old guy stalking her because he was 'madly' in love with the 15 yr old girl. He met the 15 yr old girl from his friend. His friend was the dad of the girl. He was totally obsessed with her. And he ends up killing her family just to get to her, just to be with her, and then realizes what he had done to her by killing her loved ones. He kills himself for what he had done , since he loved the girl.