Going to the Ecuador v Ivory Coast Game! Question and help please from folks going to this game

I wanted to attend the philly fan fest during the day and watch the other games until closer to game time for the Ecuador vs Ivory Coast game. Unfortunately, seems I can no longer register because it has reached capacity from what it says online. I'm a little confused though, it also says it's a fire come first serve basis, meaning that if you can't register due to the capacity you might still be able to get in if not everyone who registers goes? Also, if that's not the case, is it worth it to go early to Philly for the game or just go closer to the game time?