Much better to look nervous than to look over-confident. Don’t try to be ‘cool’ -like driving with one hand on the wheel or anything like that. Most instructors will fail you if they think you are way too confident.
That helped me get my license the first time I took the test. I was SURE I was going to fail and very nervous about that.
At the end of the driving test, as I suspected, the DMV inspector told me that I failed. I said “I knew it! But please tell me why I failed.”
He said because I forgot to lock the doors. I looked at him dumbfounded because nobody ever mentioned that you need to do that. Then I realized that he was joking and I did indeed pass the test.
Confident or not, I wish you a huge dose of siyatta dishmaya!