Hi! *grins* Welcome to AB! You must be new here. Lemme give you a breakdown of our experience on update days.
What will happen is, the 3 highest population servers will be locked...that means AB, CB, and Nagafen.
After everyone else gets in and manages to get their game played, they'll begin unlocking those 3 servers starting with the one with the lowest population- which means AB will be last.
When it comes time to unlock AB (and possibly the other 2), they'll throttle the login servers so that only a few can get in at a time, preventing a server meltdown with all of us rabid ABers all trying to get in at the same time.
If you're a prime-time player, like me, you won't get to see any content until tomorrow night. If you want uninterrupted content, wait 2 nights. There'll be a hotfix out in the morning and probably at least the morning after that until everything gets settled down and they duct tape the server back together.
Your only other option will be to take the day off of work tomorrow and play while the (American) server population is at work. Your best bet will be around 2PM CST due to the possibility of hotfix...then crash...then offline servers for a fix to the hotfix.
See, there's a whole system to it on AB.