Most likely we should not have to exclude anyone due to the content of the contest and its theme. We're still discussing the possibility of specific question categories, but any divisions that are made aren't likely to be based on age.
It is highly likely there will be questions from anime that might not be viewing-appropriate for much younger audiences (no, that doesn't mean hentai or adult, but it could very well mean things that are for more mature audiences in terms of theme and violence). Still, that will not keep anyone from ~attending~, because we are not showing video clips and questions will definitely not involve graphic descriptions of anything objectionable that might be included in the anime, and may not even refer to such materials.
What this means, basically, is that anybody can attend and play, but very young otaku, if they are selected as contestants, may not be able to answer as many questions as those who are older. Still, you never know what sort of questions may come up, especially if we continue without sub-categories for questions.
Last year, a Naruto question ended up going to a contestant who was nearly the only person in the room not familiar with that anime. This year, the question-and-answer format, at least, will be changed a bit, but likely it will still sometimes be very much a surprise what will come up on any given question.
The questions will be all original this year and contestants should expect a similar mix of questions from both popular and more obscure anime movies and series.