Advice on taking pre-reqs at MCC

I was just wondering if anyone could give me some advice on taking some classes. I have a bachelors degree, but I am planning on going back to get my nursing degree. So... I have to get some pre-reqs out of the way so I can apply. I am currently signed up for A and P, Intro to Bio, Intro to Ethics, and Microbiology starting in Jan. I am considering dropping the Micro and taking it in the summer so I can focus on A and P. I am planning on applying to programs next year and have some time to spread it out a bit. I've already taken intro to bio, but, the one I took is not going to transfer.

I was just wondering if anyone had any advice about getting them all done at once or spreading it out. I am trying to figure out if 17 credits would be too much (I haven't been in school for almost 3 years) and if I am being to ambitious thinking I could do 17.