10 years might not be enough time for some people to grow up but other classmates will have matured and gotten on with their lives.

You are correct that not to go would be stupid. If you go and aren’t enjoying yourself, you can always leave. But I doubt that will happen.

Go, talk to people you wouldn’t normally talk with, and have fun. You’ll come away with a mixed sense of how much you have/haven’t done and how much/little other people have changed. It’s an interesting benchmark to see how different lives have gone in different directions.