Never consider writing as a career... its not a career until you make enough money to live off it. So if you choose a course say B Arts, or B Comms and do a writing and publishing major or perhaps a jounalism major always think of writing (especially novel writing) as a hobby or a side career.
I want to be a writer, and am doing a B.arts. Truthfully its not gonna get me a career in writing unless i suddenly write the next great book, so i'm using my course as a stepping stone. While i'm bettering my writing techniques and learning new ways to write and things like that i'm also thinking ahead about a career. Which i decided i wouldnt mind being a librarian or a library technician. So using my arts im going to do a postgrad degree for the librarianship.. or if i get antsy anytime soon i'll transfer to another uni to do the course.
But you do have to think about another career, or another avenue that will give you money and time to spend on your writing. Also you might find along the way you don't want to write, or that you like doing journalistic style things more... so just sorta think about that a while before choosing your courses.
A good uai would be somewhere in the 80's, to get into UTS into a decent course for writing you'll prolly need somewhere near the 90's. So if you aim high, somewhere along the line you'll get into what you eventually decide to do.