I have always wanted to be an author and have been writing since I was very young; my first book was written when I was 5. Granted, it was two fragmented sentences and a a lot of dinosaur stickers, but the thought was there. I frequently wrote books, or something like books, as a child but it was when I was around 19 that I started writing seriously. As for inspiration, it varies. Cheryl was scribbles in a notebook that evolved over time, so the exact source of inspiration is unknown, whereas Gnomes and Knights was inspired by looking at a really good tree one day.
