Why? Why not?

Ok so I had an idea of a story I would totally read, but I couldn't find one at least remotely similar to the one I created in my mind so I'm writing it. So, Savannah Marie Bancroft hates her life. She isn't bullied by others, but she bullies herself. If she messes up on pouring a glass of water she doesn't think 'oh well, it's only a glass of water'; she thinks 'I'm such a failure; I can't even pour a simple glass of water' she thinks of suicide every day at least once. So, she strikes up Crowley, a crossroads demon. Her deal; her soul in exchange of being able to commit suicide without her family, friends,and loved ones being sad after it. Will Crowley help her through her depression or just move on though he's in love. Oh yeah, forgot to mention; she is 12 years old.