It really depends what you are more interested in. I personally think it is definitely more important to know basics of Chemistry or be good at it. Biology, you can easily learn at Uni. All the concepts that you need to know will be mentioned during lectures. In your own time, when you do further reading in textbooks, you will understand everything. But it is more important to have Chemistry skills. Therefore, I think you do not need to worry.
Biochemistry is very interesting.