Dear RR,
The Common Core standards are universal, and although each state or locality implements them differently. Chances are if you are having trouble with a certain math class, and you have not had trouble with math in the past, you may have a learning difference with your teacher. It will benefit you to seek out extra help. See if you can find a tutor, or even just a friend who is also taking the course but understands it better, to help you get through it. You might also consider speaking to your teacher. If you tell him/her that you are struggling and ask what you can do to improve s/he may have some suggestions for how you can get the most out of the class.
Biomedical engineering is very broad. Some biomedical engineers use high-level math every day, while others use it very little. In an undergraduate program you will most likely be expected to take linear algebra, around 3 semesters of calculus, differential equations, and statistics, as well as calculus-based physics, although the specific courses will depend upon your school. Many of your other courses may also use some of the concepts taught in these classes. However, trouble with one math class in high school does not indicate that you wouldn't be able to pass these courses. Learn how to seek out help now, because it is a skill you will also probably need to apply in college!