You are nervous about motion sickness? Like USMC said why worry now? Are you afraid of turbulence? If so, you might want to do some research and talk to a CFI about turbulence and you might develop a healthy doze of respect for why it happens. Good luck and it would be a bummer if motion sickness does pose a threat to your future flying. I am still a little confused. I think it is best for you to analyze what's exactly causing you anxiety. Heck we all feel anxious prior to a flight, if that's not natural, then you are asking for trouble. It is all part of the respect good pilots have for the flight environment etc.