What should I choose when I write a conversation? Should I write like this?
I: How are you?
John: Fine.
or like this?
Me: How are you?
John: Fine.
I don't know if there is a Chicago Manual of Style rule on this, but I think your best choice is "Me." I have never, ever seen the "I" used in this sort of writing. The "I" is usually assumed to be the writer, and the text they are writing to be them presenting information to the reader. The "me" feels more real.