It's not really weird, if you have 30-40 people in your class, you might just not care about all of them enough to remember their names.
I mean, I went to a 30-40 classes through all of high school and I always knew everyone by name. And am confident that was the case for everyone I knew. Like, it is the same people every day for a whole year minimum (and many were also in your class previous years). People from another class or from another year? Sure, don't know who those people are. But for your own class? You just kinda learn after so long together.
That said, I do find believable to know know what other people have been gossiping. I specially wouldn't knew what people were gossiping about me back then.