It is totally normal to feel nervous.
I was in your same position 8 months ago when I started my first tech job.
It is a part time dev role.
Before I started, I was going through the front end section of FCC.
But I learned to just to focus on the lessons I needed for the job.
Once you start working then you will have a better idea of what you need to learn.
A few more tips.
MAKE SURE TO ASK TONS OF QUESTIONS.
It is totally fine to ask questions.
Your boss knows you are just starting out.
There is no such. thing as a dumb question.
In the beginning, you will probably have a lot thrown at you.
But that’s totally normal.
Just make sure to take notes during meetings so you can refer back to them when you are working on your tasks for the week.
Documentation is your friend
When I have to learn a new technology or work with a new package, then I read up on the docs first.
If something is confusing in the docs, then I will look for other sources.
Communicate with your boss on future goals
It sounds like your new boss is interested in your learning and growth which is great.
While you develop a working relationship with him try to continue to update him on your learning progress and future career goals.
In my situation, I started off just working front end. But when I told my boss I was interested in Full stack, he assigned me to work on the backend of a new project so I could have more practice.
That’s all the advice I have.
Good luck on your new job!