"That's when I realised how hard it was going to be," she said. At 18 she started applying to literary agents and once she had one, it was time to start contacting publishers.
"I must have gone to 40 or 50 agents - I haven't counted because it would be depressing."
It was two years of hard work and repeated rejections but Yvette said when the call came it wasn't for just one book, but the whole series.
The young Kiwi had been recognised by Permuted Press in Nashville, Tennessee.
With seven books planned however, Yvette said she was unwilling to sign a full-series deal with such strict release dates and negotiated a four-book deal.
"I didn't want to look back when I was 40 and think it went down hill at the end," she said.
It was a big risk, because now Yvette may have to start the process all over again in order to find a publisher for the final three instalments.
"If not I will self publish because I do believe I have to finish what I started," she said.
Despite her success, Yvette said it was extremely difficult to make a living from writing and she also teaches piano and singing.
Yvette described the book as a Tolkien-like fantasy, set in a whole new world complete with its own languages.
The books follow Rafen, a boy born into slavery who is set on a path to freedom following a dream about a phoenix feather in which he seems destined to defy the greatest sorcerer of all time, the Lashki Mirah.
Although Yvette characterises the series as young adult fiction, she said she often writes in the library and is constantly surprised at who actually visits the the section where her own three books sit.
"You see these young kids and old people reading the young adult stuff but you don't see teenagers reading at all. I should be writing when I'm there but I love to watch."
Yvette has set up a website and online forum to help her connect with other fledgling writers, and she said if there was one challenge you had to overcome it was fear of rejection and "when other people get tired of you working on it". She said it was common for a first-time author to take a decade to finish a book, and another decade to find a publisher.
You can read Yvette's blog posts and information on the upcoming release at www.writersanctuary.net.
The Fourth Runi was released on November 17 and can be bought on most online book stores.