Lots of good advice here, but since it looks as if you've already found an instructor you should use the materials and course outline they recommend. That way you'll be on the same page and they'll be better able to address your questions as they'll know what your studying. I grew up next to an airport where the FBO was a Cessna Flight Center and they have always used the Jeppesen line of materials. When I attended Embry-Riddle Aeronautical University the flight course materials were also Jeppesen. The stuff from Sporty's or King are good later on for refresher info and such. I've always been a private pilot since deciding to fly for fun rather than profit and am finally about to tackle an IFR rating, so it'll be back under the hood with a CFI soon.

If you've joined AOPA be sure to take advantage of their member services. Great organization and the people there are ready to help, so use what your membership provides.

You'll certainly enjoy it, just don't get too wrapped up in the bookwork. I've seen a lot of new students get overwhelmed with the technical aspects of flying before they even got off the ground! Just get in the cockpit and fly. Fall in love with what flying is, then you can tackle the books. That way you'll have the best motivation of all, the desire to get that ear-to-ear grin back on your face!