The stalwart 'appreciators' (those who attended the 'gun' appreciation day are appreciators and not protesters though their words were sure sounded like a protest not appreciation) are on average over 50 and thus eligible for AARP membership. Old enough to vote is to set the parameters on those who are old enough to vote in an election/referendum on the subject at hand.
But you seem to be quite savvy on the crowd makeup... what would you say is the age break down? how many under 12, between 12 and 18? 18 and 21? 21 and 30? 30 and 50? over 50?