Adults only or not, if It's a first time thing do Magic Kingdom!
It doesn't look like anyone's responded to your question about fast passes, so quick run down:
Fast Passes What Are They?
They are a 'reservation' for a spot in line, when they are printed out they provide a time frame in which to return. They allow you to enter a separate line in which there is very little to no wait. Think of it as calling a head to make reservations at a restaurant, there may be a little wait, but not nearly like the wait of just showing up and hoping for a table.
How Do I get them?
The rides that have Fast passes, have a sign saying 'Fast Passes' head that direction and you'll see a large box. You enter your park ticket, which the machine reads, then it gives your ticket back and prints a fast pass. The machine prints 1 fast pass per park ticket so for 3 fast passes feed the machine 3 park tickets, one at a time.
attn: There is a certain time frame that you must wait before getting another set of fast passes, to know what that time frame is check your fast pass as it will be printed on there.
If you have any other questions, please ask, these boards are very helpful and full of great information.
Oh, and btw, I love Epcot... but for a first timer you've got to get that 'Disney Feeling' and there's nothing like seeing the castle, characters, and the few attractions designed/conceptualized by Walt himself (Carousel of Progress)