You were accepted into a college to major in computer science! First things first – congratulations!!
There are two parts of your question: “I’m deathly afraid that I don’t know enough now” and “when I finally graduate college that I won’t know anything then”
I’m deathly afraid that I don’t know enough now
Enough to what? You were accepted into school. What more should you know? What you should have is a learning attitude. You have to remember that you’re paying money (tuition) for a service (classes and instruction) so that you can learn and get better. No one knows everything in computer science. Honestly, the students who start as a CS major and think that they do perform worse than students with an open mind who are willing to learn.
So be willing to learn and grow. And if you’re bored, it never hurts to learn a new language, do a personal project, or read a book.