This is completely normal. I have been doing this for 12 years, and I still get nervous. I am new to scrubbing CV, and today I femorally cannulated, which I hadn't done before. Just know that you will learn something new everyday, and no, your head isn't going to explode! Have confidence, but don't act like you know everything. Even if you are being told something that you already know, just smile and nod, and say thank you. EAT BREAKFAST!!! And have fun!