Hello Joy,
I suggest you to atleast attempt your CET paper. If you will attempt the paper then there might be a chance that the authorities allow you to correct your Date of Birth if you will contact them and tell them about your mistake. But in case you don't give the exam there will be no chance of your admission.
Something is always better than nothing.
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile