First of all, your idea must be affirmed. Mathematics is a basic subject, and many other subjects are based on mathematics. If you like bioengineering and have the necessary determination, you can go to the websites of universities with strong bioengineering strength to see their teaching plans and related teaching materials and courseware. So it's better to know more students in this major. On the premise of learning math well, you can use your biological knowledge and make good use of library resources in your spare time.

However, it is still too early for you to take the postgraduate entrance examination. Mathematics is not without a way out. Many popular majors such as finance like math talents, and the future is very diverse.

Come on!