If you take the postgraduate entrance examination, you should make great efforts to prepare basic courses and professional courses. Try to score 400 points or even 420 points in the initial test. There is no doubt that mathematics should reach 145 or above. The marking in Beijing is quite strict. You must make sure that you do well in English and politics while doing well in math subjects in your major.
At present, there are still some books for reference in the financial professional course, so you should read more of them. The reference materials of Peking University's postgraduate entrance examination should be read, and other related exercises and knowledge should be comprehensive. This way, the second interview will have some advantages.
Don't worry too much about your background. Mathematics major is a thing with many applications. It will be great to learn math well.
Professionally, you must read some classic financial books to avoid asking questions during the second interview.
congratulations