there's no such thing as funny pedophelia
The problem is that, biologically, children turn into women/men at a pretty early age. A few thousand years ago, when the rigors of education, college, and jobs were non-existent, you could expect to have moved away from the family unit and started your own at the age of, say, 15. (Of course, you didn't live longer than 30 or 40) While our society has advanced, and the amount of growing-up we have to do to become "adult" is larger by an order of magnitude (in some sense), our biology has not. Thus, the question of when someone becomes a man/woman from being a child is quite thorny, and different cultures have different norms. Google for "age of consent" and you'll see different definitions from 13 years to 20 years or so, plus looser definitions involving things like power differential or relative age. After all, when most people died in their 30s, having a 50-year-old hitting on a 15-year-old (who probably was already the common law wife of some other teen-ager) just wouldn't happen all that much. It's also a problem that the laws versus the norms of a country, territory or popular group may not be in sync (sometimes going one way, sometimes the other).
The safest thing to do would be to stay away from the subject as far as you can. If you want to be edgy, then that's intended to be allowed by the grading system, as long as you stay within reasonable boundaries. "Sexual innuendo" is for example one of the grading levels. For example, if you make your protagonist 18 years old, then I believe your game will be allowed by reviewers in the current XBLCG territories -- but nobody can know for sure until it tries to pass review. Personally, I think that the reasons stated for rejection on the beta games ranking site would not apply to the game as you describe it, but it's really up to each individual reviewer. If you worry about legality, as opposed to how reviewers will rate your game, then I suggest finding a lawyer specializing in that area.