Mr Greylocks, while your arguments are well versed and do make sense, the word 'logic' can not be used to back up what you are saying, at least not in Supreme Overlord Moderator Illusion's All-seeing Eyes.. I looked high and low and did not find any mention of age requirment in federal regulations that pertain to this discussion.
From mcguyver's reply here
it follows that any one who acquired a replica firearm after 1998 can be charged under the Criminal Code. As such, age has no impact on legality (or in this case, illegality) of acquiring a prohibited device. It will have an impact on the outcome of the trial, when it comes to that.