Welcome to the fraternity. Yes, there will be some hazing required, but we let the coaches take care of that.
Your experience sounds a lot like mine. The hesitations will disappear over time as you learn to recognize situations in "real time" and response appropriately. I like to tell new officials that the secret to improving is to make mistakes and learn from them. The secret to improving more quickly is to make mistakes more quickly.
Your partner's advice is intended to set you up for success in your coming games. It's not possible to work on "everything" at once. So pick one or two things to work on each game and you'll steadily improve.
One thing that helped me is to keep a game journal. After every assignment spend a few minutes recording your thoughts, questions, unusual situations, things to work on, etc. Then go to work finding answers to your questions, looking up the rules you weren't sure of, etc. The process of setting goals (e.g., picking 1-2 things to work on before each game) before the game and reviewing your performance (e.g., how did you do with those items) afterward will help you improve more quickly. And that makes it more fun.
