Got accepted and nervous if I’ll be able to make it as a science major or not… I enjoy science and am good at chemisty, but I have trouble with Biology… 
I’m a freshman right now in CNAS, majoring in Math, and so far, I feel that Chem 1A and 1B are fairly straight forward. With a good amount of effort, you should be fine in intro chem. For Bio 5A, I find the material to be easy to study in lecture, but the lab is a whole different story. In Bio especially, you need to apply your knowledge presented in the lecture to different questions the professor may ask on the exam. You can’t just have knowledge in the subject. You should use that knowledge and apply it to different scenarios. You should be more than prepared if you took AP Chemistry and/or Bio in high school.