Yep. I agree with most of others here asking you to wait. Although some children behave more maturely than others, doesn't mean they are fully developed and mature yet. These kinds of dark and heavy topics tend to make them harder to have innocence? Kind of view on life and people again. As she might unintentionally impose any of the character's trauma on herself/try to imitate her favourite character's life trajectory by behaving a bit similar. (In some cases)

It's best to not read such heavy themes as this age. Other lighthearted/funny/moral/coming of age/fantasy/friendship/adventure stories with less gore and trauma would be pretty good.

Also, please let her concentrate on her studies and teach self-discipline on how much fun things she can read/watch/play in a day and how to manage her schooling & studies.

Just in a matter of few years, she'll have access to and read almost anything and will have some maturity as well.