I understand how you feel. I have a degree in accounting too. After 8 years, I decided to go back to school.
The first science class I took was Biology 189 (basic biology), I got a C I was very upset.
At this point though after getting used to my study habits again, I have been getting good grades. My school requires 3.0 to get in the program but I'm not taking chances, I have 3.53. I hope to keep it that way (or bring it up) with 3 more classes to take before I could apply.
Goodluck...we can do it!!