My memory fails me, but I'm pretty sure that for attendance at last month's San Diego Comic-Con, registration didn't open up until about 6 months prior or less. So this seems kind of crazy.
But I guess crazy or not, if you want to get a four day pass you might want to jump on this sooner than later. It's $75 for the full pass plus that gets you into preview night.
I know I'll be there and hopefully next year most of the Screen Rant crew will be in attendance as well.