You are a mathematics major perhaps because you are good at it and it’s useful, but more likely mainly because you enjoy it.
Most undergraduate mathematics is decades or even centuries old, in part because of the hierarchical nature of the subject. Meanwhile, your fellow students in biology and other sciences use textbooks that feature crucial work of the last five or ten years.
Recall, though, what you were told in orientation to college and often since: Much learning in college has to take place outside the classroom, at your own initiative. After your formal education ends, all mathematics learning will be at your own initiative.
So, you need to enhance your mathematics education now and—above all—prepare to continue it on your own after college. Now is the time to develop life-long skills to seek mathematics and to see mathematics.
Campbell, Paul, "How to Keep Up with Mathematics (Abstract)" (2002). Kenneth C. Schraut Memorial Lectures. 2.