Would you consider the narrator trustworthy?

Kathy doesn't do or say anything to make her unreliable. Kathy's narration is based on memories rather than the present. Her memories of boarding school are very much what one might expect. The reader doesn't feel like he or she is manipulated. Check out this GradeSaver link,

http://www.gradesaver.com/never-let-me-go/q-and-a/how-is-the-device-first-person-narration-used-to-create-the-theme-57473/