How late the sex happens doesn't matter. It happened. You should have rated it as such. Common sense says that when you have sexual content, you put a rating for sexual explicit material on the story. Now, you've freaked out an underage person who didn't want to read about that kind of thing. Whining about how "persecuted" you are doesn't cut it, at that point.
As for "Why don't you stop reading?", that's because everyone has critics. Not everyone's going to suck up to you and tell you how great you are. Get over it.
Author's response
What I was saying was that no one complained about the sexual content until way over 80 chapters so I wasn't aware that I should use the sex warning. No whining invloved when I complained because the ratings were trashed. At that time no one had left a review saying anything was bad. They just trashed with ratings not words. Would you like to have someone rate one of your stories Train Wreck and not explain why they said it? And as for "why don't you stop reading it?" Hey I stand by that. I'm not writing this story for any other reason than entertainment. I'm not trying to be a published author so do I really need a critic? I find it odd you think people are sucking up to me, why would they? What would that gain them? I truly only want people who like the story to read it. I can't even begin to understand why anyone else would waste their time reading something they don't like. Lifes to short for that. Find what you like and enjoy it.