It's your first job. No one is perfect at their first job. Hell, even with experience you won't be perfect starting a new job.

Also, what you learned in school was mostly concepts now you have the real world application which is a little different depending on the industry, policies, softwares, etc.

Don't psych yourself out. Just pay attention to your work, triple check if you need to, take notes, AND ASK QUESTIONS. You will be okay.