[Satan]

Nudity =/= Pornography

While that's true to an extent, this is the definition of Pornography:

Printed or visual material containing the explicit description or display of sexual organs or activity, intended to stimulate erotic rather than aesthetic or emotional feelings.

I really doubt that these girls are doing this for aesthetic or emotional feelings.
There is a difference between reading Playboy, and sharing explicit pictures of 11 year olds.
While I agree exploring your sexuality isn't bad, its only good if you're exploring it in an environment where you aren't going to be damaged, your reputation won't be damaged, etc.
& Sexual education needs to be made earlier, I agree, but it needs to have an early focus on the negative effects of it.