I think we need a time out for a second, what set is she talking about, if she is talking about the "sammy" set, get that shit out of here. edit: I hope im just being paranoid.
I get the feeling a lot of these models and celebs lie about certain content being "underage" just to get it scrubbed quickly. Its probably stuff she did when she just turned 18, so she can plausibly claim she was underage and there's no proof to the contrary, at least not proof anyone's gonna risk to believe. And its probably her way to capitalize on any potential future nudity, or at least the promise of it.