Emma/Abbie.
He's a guy, of course he doesn't get that. The only way his idea would work is if you just go to the courthouse and... have a potluck up in the lounge or in someone's apartment. If you want a specific cake and not just something you can buy at a grocery store, or a caterer, or a band, a venue, you're gonna have to stick with something.
I don't think your dad would want you to wait for him. i think he'd understand. If we wait for things to be perfect and for there to not be any snags or complications, whatever it is we're doing, we'll be waiting forever.