You are gonna get your ass beat. Just remember, you are there because you want to learn. If you won any fights day 1, then who are they to teach you and how much can you really learn from them?

You will panic, the more you learn to stay calm and think of it like a game and not a fight the faster you will learn. Focus on the relaxing and one simple thing to remember, don't worry about how you were overwhelmed and forgot 99% of what you saw. People with years of experience are missing most of the details of what they were shown each class too.