OP, in your first post you mentioned sitting in on an Algorithms class. That is a sophomore level class and you aren’t expected to know that quite yet. Don’t think you’re underprepared.
Perhaps get some programming books to get a head start. Or take a Discrete Math or Linear Algebra class at your local community college to get some early exposure.
I have heard that a lot of CompSci majors have had little actual programming experience before starting college. Don’t feel disadvantaged or feel that you have a case of imposter’s syndrome… Everybody has given you support and advice on how to succeed.