RE: Night Land Journals [comments welcome]
The thing about the world is that somewhere, there's a fifteen year old girl that likes it in both holes. I'm not at all sure how anyone can say that it's out of the realm of possibility for a teenage girl to be very sexually active and experienced. Many people form the opinion that it's impossible, or unlikely, because it wasn't something they have experienced. People consider the culture they are in, where it's "sin" for a youths to be sexually active, and take those feelings as cold, hard fact. "We" don't like the idea of a fifteen year old girl getting plowed by some old guy, therefore she wouldn't like it. I'm not at all sure where I stand on someone that young being emotionally capable of dealing with having sex, however. Is it that young people literally cannot handle sex on an emotional level in their early teens, or is it that we live in a culture that turns it into a taboo and scary thing until we're adults? Bump the uglies, go to hell, don't pass go. We should also consider that there are plenty of adults that aren't emotionally capable of responsible sex, let alone carrying on a healthy relationship. So, does it come down to the individual?
At fifteen, a girl can be well developed. I'm not sure why someone would think that your character cannot have decent sized breasts and pubic hair at that age, considering the incredibly diverse way organic life, humans in particular, tends to grow. I'd also wager that a fifteen year old girl's vagina can take two cocks at once. Physically, there shouldn't be any problem. It isn't a question of biology, so much as it's a question of experience. Is she accustomed to such a stretch? If it's a dream world, where the normal rules are thrown out the window, then it's even less of an issue. Basically, whoever told you this doesn't actually know how a vagina works-- that's even ignoring that girls/women tend to have different vaginal widths.
Your character could have gone through and been done with puberty by now. If she's well developed now, it isn't hard to think that she started puberty when she was eleven, ten, or even as early as nine. There's nothing wrong on a physical level here. Maybe the pieces fall together in a convenient way, but they tend to for protagonists.
A fifteen year old girl that is mature and ready to have a lot of crazy sex.
A a ten year old boy, who survives a killing curse, is swept into a magical world, becomes a sports star, takes out an ogre, learns old secrets nobody else could figure out, and then proceeds to unravel and foil the plans of one of the GREATEST wizards of all time. He then does this, in varying degrees, for seven years straight.
I'm sure one of the two happens to be more believable. All that matters is how you write it.
It doesn't sound like these three people thought out their criticisms very well. It sounds like they were motivated by the squick factor, and then said some less than true things to back up their issue with the character ages. Does that mean they are wrong for mentioning the squick factor? I don't think so.
If you want to sell this book, it'll probably be more difficult with the protagonist aged as she is (which you're well aware of). Lot's of people are going to have that squick factor. If you don't mind leaving your artistic vision at the door, and making compromises for the sake of success, then it MIGHT be a good idea to change her age. Then again maybe a controversial aspect like this is just what you need for the book to really be successful.