Hi sharmarahul12,
Have you taken any other practice CATs besides this one? If so, then what were your scores? If not, then you should consider using the 2 practice CATs that you can download from
www.mba.com. Those CATs are arguably the most accurate CATs available.
You have to keep in mind that the accuracy of a CAT result depends on a number of factors, including how 'realistic' YOU make the experience. You should take the ENTIRE CAT (including the Essay and IR sections), away from your home, under as-close-to-'test-like' conditions as possible, at the same time of day as your Official GMAT, etc.
If you're concerned about this CAT result, then you might want to push your Official Test Date back and continue studying.
GMAT assassins aren't born, they're made,
Rich