There were two things going on: 1) I had already established in my own mind where I wanted to go with the next series, and having James around as a Grey Eminence would have complicated matters. He had had an amazing life and it was time to bid him good-bye.
Once I got to high school and auditioned for a play and got in, I thought this was really what I was looking for. Once that had got cleared up, from 13 on, that was it.