I defended a 17 year old charged with videotaping himself and his 16 year old girlfriend having sex. Under the law, both of them are child pornographers, subject to horrifying prison terms, even though they didn't intentionally share the video with anyone. Fortunately, I was able to get my client probation, but that is more a matter of the prosecutor and judge being unusually sensible than any legal defense.
I don't have any strong opinions about what you do if under 18 teenagers start making porn videos and distributing them (no distribution in rea's case as far as I know). But the point is that teenagers do in fact get charged with this stuff, and the consequences of getting caught up in the legal system can be severe.