Hi Isra,
It sounds like you have made fantastic progress over the past year and have done things that scare you and feel better e.g prouder, more sure of yourself for it- that’s fantastic.
Three things I can think of about your internship (but tbh from your post it sounds like you are absolutely going to ace it 🙂 ) are:
1) a good book called ‘feel the fear and do it anyway about facing your fears
2) on the first day just remind yourself of all the other scary things that you have done and overcome just as you will with this one
3) keep reminding yourself that by taking the internship you are actively pursuing your dreams and goals and that is more than some people.
Very best of luck!!