Being a biology major is really great, but it takes work! I am just going into my third year as a biology major. Generally your first two years of biology courses will be the required 100 and 200 level biology courses that your school makes you take (for me I had Cell Biology, Evolution and Diversity, Ecology, and Genetics/Molecular Biology) and then after that you can usually take electives which will be whatever you want and whatever your school offers. You will also probably be required to take some chemistry, and maybe physics and calculus if you are unlucky! It is definitely possible to get a good GPA if you actually work at it and like biology.
What are your plans for a job or future schooling? Usually you can kind of tailor your experience in undergrad towards what you want to do after graduating!