How can adult children get money being held by their guardian?

More information is needed here to help with trying to figure this out.  Was the money left in a trust with your Aunt as trustee or was it just left in accounts for you with your Aunt as signatory?  Either way you need to get a hold of the documentation, either the trust document or the account information.  You need to have yourselves declared as adults in th majority and to dissolve the trust agreement or transfer the accounts to you.  Your Aunt - living in New Zealand or not - should be able to execute the necessary documentation and send it to you.  I would consider speaking with an attorney in your area once you have all the documentation.  Good luck to you.