"No I'm not the next JK Rowling," she laughed. "People like JK and Philip Pullman are world famous. I don't think that's going to happen to me."
Catherine, from North London, has never thought about being famous.
"Now it's published I'm very scared," she said. "It's weird that other people are actually going to read it. When I write, I write for me."
Call from an agent
But that all changed when she showed Mirror Dreams to her parents.
"The first thing they said to me was 'You can't spell', she said. "But then they asked if I wanted to send it to this person for some advice.