Speaking from my experience of studying for, and passing several ACCA papers while waiting for uni.

I was from science stream too (but I did some prinsip akaun for SPM).

Generally, its not hard. If you are able to grasp pre u science and math, and have decent english (but IPTA accounting may be in BM, idk), accounting generally shouldn't be an issue.

If you want to get a feel of what studying accounting is like, I suggest you create an account on opentuition.com and read up on ACCA notes for papers F1, F2 and F3 here http://opentuition.com/acca/

Have fun!