Well, coming from my background, we learned a bit in fourth grade, but mostly because my teacher was a huge mytho buff. Then in eighth grade, we were going to learn about mythology in the last few months of school, but I didn't, since I moved beforehand. Most of my knowledge about mythology and gods is from my own interest. People who go to the school are supposed to come from all around the world and its countries, that plus the fact that everyone's history is different is enough to see why not everyone would know about these things.
Secondly, and I'm only trying to remain diplomatic in this, elementary grade teachings about God and gods does not teach the immense levels each one has. Most of what they teach is their names and the major things they stand for, as D'evil has stated.
And, no, D'evil, I would not think there to be a demigod elementary school. One reason is because in my sense of demigods, their powers do not begin forming terribly noticeable until puberty age, when a teen's hormones are all out of whack and their body is changing. My other reason is one I will not reveal at this moment, because it discloses information about a major plot point I hope to unveil later in the roleplay.
And Beauty is right in that people can choose to be sociable or not, free will and all that. If someone wants to be quiet/shy/aloof, even, then that's their character. As such, anyone can be a charismatic social butterfly. But, as far as roleplaying goes, characters tend to change or have an inner self. Just saying.
