You say you are worried you are not ‘good enough’, but what is good enough? You say you are about to start a course, which suggests you have been given a place on a course? If so then you must be ‘good enough’. And once a person has a place on a course, the deal is that you are there to learn, to practise, not to already be expert. So throw yourself into learning, play, dance, make mistakes, laugh at yourself, study, wonder, enquire, try, fail, succeed, scream, etc etc.
I used to get 3/4 way through a painting and then be afraid to continue becasue I knew that what I ended up producing would never be as good as what I had imagined in my mind. But then one day I had a breakthrough and I just thought paint, paint, paint! And sure I have screwed up paintings, but I have also painted many fabulous paintings, and I have spread a lot of joy by painting commissions for people.
Why are you doing the course? Because you love creating art, or are you doing some test of life / the universe to get an answer to “Am I good enough?”. Maybe somebody told you a long time ago that you are not good enough, and part of you is sure that they are right. But that presumes that there is a real thing that is ‘good enough’, and isn’t that all opinion? It’s not like one person has a hot line to God and they KNOW what or who is good enough and who isn’t.
Also plenty of people have phases in life where they produce great work and phases where they don’t, so there aint no such thing as ‘being good enough’, yeh?
Once, when I was young and at school, I asked a question in my art class, my teacher sneered at me and the whole class laughed, I felt really humiliated, but I’ve sold hundreds of paintings, so they were not correct…
So, I think you’d do well to take the focus off of trying to get some validation and put it onto learning. Dive into it, imagine if you had total freedom to learn, to not have to know already. Imagine how much more you would get from the experience then…
Good luck to you