I presume that you have your tickets as part of a package. Since there's no way to access or use them before your checkin date, the system doesn't give any access to the FP+ system.
Now, if you've purchased tickets separately from your hotel room and linked them to your account, they'll show access for the immediate next 30 days from today. When you get to 60 days from your hotel date it'll also open up the FP+ window starting with your checkin date. It does this because the system doesn't make presumptions that you're definitely waiting to use that ticket on your 4-months-from-now hotel reservation (for all they know you might be going to visit Aunt Betty in Kissimmee and need to go to the parks on that ticket, and you'll be buying a separate ticket for your future on-site reservation).
But if you bought your ticket separately from a hotel package and yo *can't* see the next few weeks as being available to make a FP+ reservation, you should think about calling the Help Desk. (But if you have a package, you're all set)
-Rob