First off, fill out your location in your profile. It makes it easier to give you help when we know where you're located.
As for these "events", depending where you live, there are usually games running every month or every couple of weeks through the summer. Once you're 18, show up at one of these games and you can get to see a lot of the guns. There are pretty much always age-verifiers as these games that can verify you. Otherwise, contact a rep for your area and get verified that way.