I agree with BoomerangBen to a greater extent.
My best advice is that on your first lesson, treat it just as a famil flight and enjoy it. If you try to analyse the theory of what is going on in too much detail, you won't actually get the best out of the flight. Keep your eyes out of the cockpit window. Get used to the strange new effects that you (as a plankie) will experience.
Just listen to the instructor's brief, take it at face value, then go out and do it. Keep it simple and save the deep and meaningful questions until after you get back.
Enjoy it (you will!) but you have been warned, you are about to begin taking the highly expensive and addictive drug known as Rotree. And be aware that you are going to get very frustrated having to ground taxy to the runway next time you want to fly a plane....
