"I'd spend hours there -- it was just like the bookstores with the old wooden bookshelves I'd read about."
It was also in Masterton that Morgansen, now a primary school teacher, first discovered her love of writing, as a pupil at Fernridge School.
"Our teacher, Mrs Cameron, gave us these awesome writing exercises -- for example, she'd put some music on, and just let us write.
"I do the same exercises with my own students, and now half my class are writing their own novels."
Morgansen first began writing The Elm Stone Saga at 16, after stumbling across the name of its heroine, Aristea, in a names book.
In the books, teenage Irish witch Aristea discovers her magical abilities, and starts an apprenticeship with supernatural lawmakers The Council of White Elms -- which has become infiltrated by dark forces.
Morgansen, who describes herself as an "epic sci fi and fantasy nerd", was inspired by a range favourites from her youth, including The X-Files, Roswell and Harry Potter.
The end of JK Rowling's popular series left a gap for the young Morgansen, who struggled to find young adult fantasy which was accessible, but still had an edge.
"There was nothing in between the teenage love triangles and the longer, more plodding adult stories like Lord of the Rings.
"I'd probably compare The Elm Stone Saga to the later Harry Potter books, where it gets more sinister -- the earlier books were fun and fantastical, but mine go straight to the dark stuff."
Morgansen spent five years writing and three editing her first book -- which was split into the two volumes, Chosen and Scarred, after a publisher told her it was "too huge" to read comfortably.
Since then, the books have garnered a loyal fan-base, and have been particularly sought-after by older readers.
"I just got a message on Facebook from a woman whose grandma loves the books. So my biggest fan would be about 84."
Her advice for other writers is to embrace their imperfections.
"I'm a terrible perfectionist -- I have all these unfinished stories on my computer that I thought weren't good enough. But, I realised I had to take a risk.
"As I tell my students, nothing bad actually happens if you make a mistake."