Hi there, there's no real reason to worry about IR. ir doesn't have any impact on your 3 digit score, also, because it's brand new, schools won't weight it heavily.
Good luck
What is worth pointing out, is that the IR tests the same skills as the Critical Reasoning. The only considerable difference is the format of the IR. So, if you have prepared for the other parts of the GMAT, you should not have problems with the IR.