i believe we are moving it to this saturday. the 3rd of march

Unfortunately what your dad says goes, as long as you're living there. So you've got a few eyars yet. However, all hope is not lost!! You can speak with him, show him different sites such as this one, the Chicago Airsoft Association (if it even still exists, I'm so far out of the loop I have no clue), different team sites, etc. You could also make the dreaded comparison to Paintball, and that for a decent paintball gun, people will go out of their way to spend 1k+, and don't care about the realism factor. We care about the realism, and it's smarter to have a backup weapon, AND we're spending less doing it.

Here's a thought: If he won't let you have a pistol, you could go for one of the Tokyo Marui shotguns... Sure it gets ten shots a shell, but it's less expensive than a GBB AND cooler! Who cares about lugging around two rifle-sized guns.