"I thought it was a participation email. I couldn't believe I won, it was so exciting.
"It was a lot of fun and winning made me feel pretty good about myself."
Zach will go to Wellington where he will attend the dress rehearsal and see his piece performed.
He is thrilled to be seeing his composition played by professional musicians.
"It will be quite an intriguing night and not as much pressure as performing."
He says Virtues of a Teenager is a pretty post-modern piece.
Zach started work on the piece in February and entered the competition in July.
He says he originally created Virtues of a Teenager for a performance which would include a pianist, violinist and baritone voice.
"As there are not many arrangements for that sort of trio I decided to just write one so we had something to perform."
Zach is a pianist and has been playing for about 13 years.
"I enjoy the satisfaction of learning a piece and being able to play it well, knowing the meaning behind the piece."
He says winning the competition has opened up another tertiary study option for him.
"It's eye-opening and I enjoyed playing with ideas and developing the piece."
Western Heights High School head of music Adam Hague says he is very proud of Zach winning this competition.
"He worked hard to complete his very ambitious original composition titled Virtues of a Teenager. He is the first to win this particular competition for our school as far as I'm aware.
"It's great for our region as all other winners this year have been from major cities such as Auckland, Wellington and Christchurch."
Adam says the four professional musicians who will be performing Zach's piece this weekend are all very impressive.
"It will be wonderful to see his creation brought to life in this way. This is an amazing opportunity for him."
The annual NZCT Chamber Music Contest acts as a springboard for the musicians of tomorrow.
It sees alumni appear as members of orchestras and chamber ensembles, in New Zealand and overseas, and embark on successful solo careers.