Number system

I thought I had a presentation today for my Accounting Communication class. I prepared my Power Point slides, practiced my speech and printed out my presentation slides. I practiced my speech like the whole night just to be well-versed. I even dressed business professional for my presentation. When I walked into the class, I was surprised that my name was not on the board.

Me: Why is my name not on the board?
Professor: "What is your number?"
Me: There a number? * the class laughed* I don't know. Where did you get that number from?
Professor: Yes there is.
Me: Errr, I don't know.
Professor: Your number is 16.
Me: Do I go today?
Professor: No. You go next week. You didn't know that? We are using the number system now.
Me (whispers): I circled today I remember...

I asked my friend. Did I not circle Sept 29. He said yeah, I think you did. Even my friend vouched for me. Why would I go through all the trouble to dress up and get ready for a presentation which is due next week. As a matter of fact, I did circle Sept 29.
But, oh well. I guess I go next week then. Hopefully, I don't be speechless like I did for my first COM 135 class. The longest silence of my life. And then, I got so scared I walked out of the room. Yeah, that's what happened to me.