Retaking classes in undergrad..

I'm just in my 2nd semester of my ADN program, planning on doing a BRN after I graduate with the ADN, then working for a few years to get experience, then start applying to CRNA school.

I have a few C's here and there, mostly from my lack of effort as in incoming freshman. I have a C in a chemistry class and I think I'm going to retake that for sure, after seeing that they really look at the science classes.

My question is, how many classes can you retake before the admissions board at CRNA school start to wonder, "Why did he retake all of those classes?" I mean, there are only about 2, maybe 3 classes I'd like to retake to get A's in that I had gotten C's in before. It would boost my GPA pretty good. Lately I've been getting A's and B's, but yeah, I do have a few C's in my past.

Should I retake a few classes? How many classes is too many to retake? Do they really look down upon retaking classes?

Thanks for any advice or opinions!!!