Ath the CIA on your first or second day there you will take a math evaluation test along with a similar sort of test in writing. You will then either be placed in B Block (the first real set of classes at the CIA) or put in A block which is three weeks of remedial writing and math instruction. People at first are usually embarssed about being an A-block student but after several months of classes everyone forgets and as long as you can cook you will hold your own.
The math classes at the school (Culinary Math, Costing, etc.) are not too hard, but a lot of people do struggle with Costing. There is, of course, lots of tutoring and extra instruction available, so you should do fine.
While I don't know you, I still would say not to worry about it.
tim