You already did half the novel course without realizing it?!

It's true, I was finishing a chapter of the novel I started for the basic institute course, initally called "The Sagemount Chronicles" but changed to "The Mystic Trilogy," for obvious reasons. =P
Then I got a letter in the mail claiming I was accepted for the advanced novel course Jan recommended me for (YAY love you Jan =D) and I took a look at the assignments, and realized I'd already finished half my book. XD Nevertheless, I've paid for the course and I should get my materials within the week and I can get started. =)
I don't think it matters though, you can use a book you've already written two times over and in the process of a third draft with a vague outline for the entire trilogy, right? XD Yeah, it's already in the middle, but I don't think that matters as long as you can make it better with someone's advice, huh?
Or do you have to write a new book? Not sure. o.o