Dave,
Ok glad to have helped but I have a further suggestion.
Would you consider adding a warning for those under 13, or perhaps just a general warning? Some of the debates, especially in religion can become very heated and emotional; many younger people, and for that matter some not so young, might have trouble dealing with such advanced themes. A warning might be enough to encourage children to be aware and would also protect you from potentially irate parents.
Up until now you have had an age limit posted and you have no knowledge of how many under 13’s have not registered because they saw the age limit.
Hope this helps.
Cris