Probability theory depends on many contents of calculus, especially double integral. If you know calculus thoroughly, it will be of great help to other disciplines. Be sure to buy a matching after-school exercise selection solution, there are many detailed knowledge points that are not available in the textbook. Probability theory and mathematical statistics are two parts of a book. Only by learning the former well can we learn the latter well.

Linear algebra can be studied independently in universities and does not depend on other mathematics. The textbook is abstract at first, but the structure is simple. The reason why it's simple is that the contents are the multivariate "equations" that you learned in high school. It is abstract because many new concepts and properties have been added, but it is still a system of equations (soul) after all. You can refer to the postgraduate entrance examination books, such as Li Yongle's "Guidance Notes on Linear Algebra". Doing problems is the best way to understand. Persevere, I wish you a happy study.