I have paid the 1st installment; but I hadn't told them that I've 40 percentile in Sept CMAT. Would it be any problem later?

Now that you have already paid the first installment it wont be such a big problem, but just to be sure call up nagraj sir and tell him your marks he can help you. Nagraj sir or Gururaj sirs phone number is given in the official website of the college. if needs be you can also contact me. my number