Writing a bloody book shows that she likes you very much, but her behavior is too extreme. As you said, you are still young and immature. There is no guarantee that she will do something more outrageous, such as self-harm or something.

If you don't like her very much, just communicate with her directly. This is a technical job, you should master the tone, method and even the environment. This kind of girl is very sensitive

But you must tell her categorically that you appreciate her bravery, but this way is not very good. You won't talk to her about friends. The girl you like should be a girl who is good at everything. That was later, like when I was in college. In this way, in order to please you, this girl will work hard towards the excellent appearance you described. Even if she can't catch up with you, she will grow up and become mature, and won't be hurt too much.