I write fiction on a pretty popular (not mainstream or "official", just gets a lot of hits from writers and readers) site, along with a few thousand other authors. One of the stories I'm in the process of writing I've rated T for Teen, meaning it's suitable for people 13+, on the site's official rating system. Now, I've had one girl write a review for every single chapter of what I've posted saying how much she likes it, which is of course flattering. She's mentioned several times that she doesn't want to see any "kissing or snogging" as it's "gross". I thought nothing of it.
However, today she happened to mention that she's 12 years old. This was a pretty big shock. She's 12-no wonder she thinks kissing scenes are "gross", and this piece that I'm doing is about to mention that and a lot more. It's not a Mature-rated work, but I will be briefly alluding to and skating around some very "adult" things, like handcuffs lying on the table, emotional abuse, and two people waking up in bed next to each other. The main male character, whose POV I write in for every other chapter, is Not a Nice Man. The main female character is about to toss what precious few morals she has aside for this guy. I'm not trying to write about Hannah Montana and her giant moral compass, I'm trying to write about real people.
My point is, I don't want this girl, who's probably never even kissed anyone, learning all of this dark stuff second-hand from me or going and searching for it online. She messaged me today in the messenger system, opening up a conversation, and I need a way to suggest that she probably shouldn't read any further because she's not going to like what she sees. However, I would like to do it in a way that sounds polite without being patronizing and at the same time doesn't make the story sound super tempting to keep reading. Can anyone help me with the wording of the message? Am I out of line for trying to warn her in the first place? In a year or even less she'll "officially" be old enough to read it and the story's ratings are just guidelines, but I kind of feel like I should say something.