I mean, yeah. But also, this isn't really any different from kids not being allowed to drink alcohol before a specific age, movies and video games having age minima, etc etc.

And I would surmise the same reasoning applies: On average, someone so young has neither the mental development nor the life experience to be able to judge well what they are doing with their own information and how to judge/process the information they get shown.

Of course, this should happen in conjunction with actual education, like I at least had for alcohol and stuff. But it's an entirely normal thing if it happens as part of a multi-step process (and I am not australian enough to judge how well those things work out in australia in general).