If your school runs a chess club, you should join if you can. You may be able to attend a chess club at a neighbouring school if there is a before- or after-school chess club. Some schools with a shared relationship may allow you to attend a chess club at their school during school time. Some school care programmes and holiday programmes like SKIDS may run a chess club. And some GATE programmes like MindPlus may offer chess. Investigate your options.
University chess clubs are often open to former, and intending students, or to anyone interested in chess.
If you are in Auckland then you have a choice from a wide range of chess clubs. All are very fine clubs. You would normally choose the closest club, that meets on a day of the week that you are free to attend. Some very keen chess players, including students, will join more than one chess club.
In Auckland students (and some adults) tend to go the chess club with the strongest players. Which club this is changes from year to year. Currently this is the Auckland Chess Centre. This is a mistake. Unless you are one of the top 10 (student) players in the country, you will receieve excellent training and strong opposition at any Auckland chess club. Indeed, by crowding into one chess club you have less chance of playing strong players and less chance to get personal attention and coaching. Instead choose a local chess club. If the Auckland Chess Centre is your local club consider joining the Waitakere Chess Club instead, which is close by.
Outside of Auckland you are usually limited to a single local chess club for OTB play.
You should check with each club, on their website if they have one, as to whether they are meeting and what restrictions are imposed.