Don't want to worry you but..............I'm going to anyway. An instructor once told me of how he was taking a student on an introductory flight. Now this guy 'flew' flight sims and talked the talk. Seemed to know his stuff. When he asked the instructor if he could handle the controls during take off, the instructor allowed him to do so, although normally he wouldn't.
The take off roll was uneventful until the aeroplane lifted off the ground. At this point the student shouted 'No, no, no' and pushed the yoke hard forward. The instructor retook control and landed heavily swung off the runway, thinking that the guy had seen something wrong. After recovering his composure the instructor asked what was wrong. 'I just got scared'. was the reply.

Seems the real thing is a bit different than sims:rofl
When they taxyed back in. The guy had got over his fright and was last seen trying to book another introductory flight!
But seriously don't worry, just do exactly what the instructor says and relax. It is really very hard to get hurt in a light aircraft on a clear day. The 172 is a nice cuddly safe aircraft. Turbulence is mostly a non event, after a while you hardly notice the smaller bumps. If you don't land with a big smile on your face. I will be surprised.
