i wouldn't use first person. most teachers don't like that in essays and is usually inappropriate (style-wise) unless explicitly needed for the topic. if it was an APA-style paper (for science, science related subjects, and scientific research) you could use "I" and "Me."
instead, say something like "There is sufficient evidence from the book to support Johnson's theory that the main character was actually a female child." ...it's your main "claim" or "argument" that the paper will support.