Firing a shotgun and a pistol are vastly different. A shotgun you should sleep the trigger, a pistol should be a slow deliberate squeeze. You should have a firm grip. Don't be afraid to take extra time with each shot now to develop good habits as it is hard to unlearn bad ones. Try to get someone to watch or video your trip so you can see what you are doing.
Keep at it, you will get it and enjoy it!