Being a novice surfer, I avoid going out when the surf is too big and unless the waves are tiny and the sea calm, I also avoid going past where I can touch the bottom without a surfboard or something to float on.
Things can change fast in the water and you can easily find yourself in trouble if you push your limits and don't have your wits about you.
If you know your limits and stay within them, you are far less likely to find yourself in trouble.
On top of that, every person living in New Zealand should learn how to swim - even if it is only enough to reach the edge of the pool if you fall in.
Get a friend who can swim to take you to the local pool and give you some lessons.
If you can't swim, or are not very confident, stay away from beaches, rivers and lakes.
Wading in ankle deep water is not likely to be a problem but one freak wave could be enough to knock you off your feet and sweep you out to sea.