Consider section
66C of the Crimes Act 1900 (NSW).
Consider also section 77 of that act, which provides for
consent not being a defence to (
inter alia) a section 66C offence,
where the child is under the age of 16.
Where people (especially young people) can have a problem is that,
age of consent or not, creating, and/or publishing an image (whether still or moving)
of a person aged under 18 (even yourself), can still amount to one or more
child pornography offences (variously producing, possessing, and distributing).