Most J3 Cubs need use of the rudder to fly properly due to something called adverse yaw. If you would like to research, there was a good article in Model Airplane News a few years ago by Garry Yarrish I think.

Get a nice Sig trainer and build a Cub while you are learning on the trainer. Great Planes and Goldberg....both sold by Tower are good kits. If you want an ARF, I think Hangar 9 still has one.

good luck and have fun