What do you think of this from a sixteen year old? I am wondering how to guide her?

I think she is a talented writer. Her poem is vividly moving and beautiful. Despite the morbidity, coming to terms with death is a life-affirming act. If you want to guide her, perhaps you should encourage her writing and accept her as she is. If she writes this well at 16, she will be amazing if she keeps at it and grows! It sounds like she has profound depth and creativity.