I hear people say they shoot good groups a lot. Being as new to archery as I am, I have no idea what a good group is. What size do you consider to be a good group at 20, 30, and 40 yards. I have yet to shoot more than a few arrows past 20 yards. I can easily get groups at 20 yards to group in a 3inch diameter. Is this considered good, bad, or fair? I don't want to be moving back too soon.