It is only natural to feel like this and i'm sure you will find that most of us on here have felt like this at one time or another.
You probably don't realise how much you already know, and that you will be able to transfer your knowledge to your course. There is plenty of support on here and at your college. (If you are doing it at college?)
If you get stuck, the members on here are a lovely bunch and very helpful, you will probably find a lot of answers you will need for your forthcoming assignments already on here.
Best of luck and have faith in yourself.