If I take a Mandarin language course in college, will I be fluent in Mandarin by the time I get my bachelor’s?
I don’t think so. Learning a language in school is learning a language which is not quite true–I know it! China is very large, different areas have different ways to speak Mandarin, and they have different words. And some expressions even in Beijing won’t be appeared in books. So, the foundation is, learning Mandarin in college, then if you want to speak Mandarin fluently, go to Beijing, even other parts of China.