Should I be nervous about graduating high school?

So, it is my 2nd semester of high school on January 8th. I have been accepted to Oklahoma State and start in the fall. Though, for some reason, I am nervous. Scared actually. To go into the real world, to graduate. I can’t really explain why I’m scared. I just don’t want to be scared anymore. What do I do? How bad is it out there? Will I enjoy it?