As an afterthought.... Ask if your school is a Cessna Pilot Center (CPC). If so, you might want to look into the Cessna "Cleared for Takeoff" kit. It's a good addition to a ground school and has video clips shot from inside the plane of what's going to happen each lesson. A lot of places will cut you a deal on the price if taken concurrently with a ground school.
Be wary of any course or school that has you memorize answers for the written exam. The FAA has caught on to this and will be randomizing the questions very soon.
Private and instrument are the most difficult ratings unless you get into your CFI(s). Reasons being;
At the private level you're getting into a whole new world. It's the most important time to be sure you're learning the right things and good habits. Less than a third of the pilots in the U.S. advance to any higher ratings.
At the instrument level, you get some in depth "If you don't respect it, it'll kill you" stuff. Get a real good instructor for this one.
If you get into your commercial ratings and had a good instructor for your private, it's all basically review with tighter tolerances on maneuvers.
Well, you also get to learn some new really fun maneuvers.
Another big advantage to a ground school is hanger flying with the other students. You can learn a lot just by listening to what they're doing right or wrong. Maybe even hookup with someone to trade off riding backseat with so you can learn for free.
If you have any specific questions, feel free to pm or email me.