Summer College Class?

Hey all!
I am a current sophomore and I know that I want to go into healthcare, (Nursing, medicine, etc.) I am just not sure exactly what. This summer, I want to take a class at my local community college in something that I am interested in and relates to my future career. (I am not just taking a class for the sake of boosting my resume, I am actually very interested in the topics of these classes). Which class do you think would be the best? Below are my options.

1.) Intro to Infectious Diseases
2.) Contemporary Biology (Cancer, stem cells, humane genome, etc)
3.) Human Nutrition

They also have an anatomy class and a physiology class but I don’t think I would do well taking either of these at only fifteen, especially because it’s not meant for high school students. Has anyone taken this class online that wasn’t ridiculously difficult? If so, what was the website/college?

Thank you so much for your help!