If the club opens up a few hours before the show sometime during the day, there may not be anyone at the door and you can just walk right in. You may have to kill a few hours inside though. I would just hang around the door and wait until an opportunity arises. If you see J, explain your situation and ask him to put you on his guest list. Get a fake ID. Bribe the door man with a $100 bill. Find another door into the club and sneak in. Tell the doorman you just want to go inside so you can fill out an application for employment. If you see the opening band hauling thier equipment in, grab an amplifier or something and haul it in and look like you know exactly what you’re doing. Walk into the front door before the show carrying a guitar case and maybe people won’t mess with you. Do whatever you can… About 8 years ago I was too young for a show and I ended up sneaking into another part of the building and I was at least able to listen to it. Whatever you do, don’t give up. You’d be suprised what you can get away with in this world.
If you make it in, say hi to me, I’ll probably be there.