1. I would say my biggest challenge was confidence. Still is. No matter what specialty you go into you will always be questioning yourself in the beginning. And this is a good thing, right? You don't want to think you know everything, because you don't.
2. At 6 month I was just hanging on for the ride! At one year, I felt competent enough but very green still. I think that's normal. It takes year (s) to feel comfortable in a new role.