You do not need a WWC Check.
Based on your answers, you do not need a WWC Check because your activity is unpaid private or domestic work.
Section 9 of the Working with Children Act 2005 defines child-related work as work in any of the occupational fields, involving contact with a child that is direct and not incidental to the work.
Some organisations have their own policies regarding who needs a Check. Confirm this with your organisation.
If your circumstances change, go to 'Do I need a Check?' and answer these questions again.