Actually, you don't have to be too nervous. You don't need a lot of banking knowledge now. Many college students in our bank became monks halfway, and their majors were not right at all, but they did well.
The key is to give people a sincere, down-to-earth and serious impression. Don't pretend you don't know, and your self-confidence is bursting.
As long as you are smart and flexible, people will choose you!
I hope you succeed!