Just go for it! NZ is a great place, i spent 8 months there a few years back and loved it! You'll always regret it if you don't take the opportunity, and if you feel it isn't for you you can always come back - it may seem a long way away but once you start getting on and off planes its really not that far! Also christchurch is great fun, tonnes of cool stuff to do in and around there, its like a massive adventure playground!
In my experience any opportunity to go and explore the world should never be missed, especially not if you'll be getting paid to be there!