Excuse me, class started when?

So I begrudgingly headed off to class # 4 from the end last night and sat down. One of the other ladies said, "you were busy last week?" Stop...think...why would she be asking me that? "Um, I guess." "Yea, we thought that's why you weren't here." *Thinking to self, I wasn't here cuz there was no class.... Checked calendar...Class #1 clearly listed LAST Thursday. Hmmmmm. 17 years of college and never has such an event happened. I, have either lost interest...which by the way is ENTIRELY possible...or, well, I can't really know what happened. I was happily at Freshman open house with my daughter and 500 of her closest friends. That's my story and I'm sticking to it.