2 points Yellowhawk

1. Yes, it is nice/best to have the trims centered mechanically for takeoff. That way if they get accidentally bumped while transporting all you need to do is center them to know they are ready for takeoff. Nothing to remember.

2. Don't touch nuthin. Like Ken said, you're not quite ready to do that yet. Next time at the field have your instructor show you how to do this properly. All too many times I see experienced people do this backward.