Hello aspirant,

You can appear the CET examination. The basic eligibility criteria for CET is:

The candidates should be Indian nationals and should have completed their 12th standard or equivalent examination from a recognized board or university with Physics, Chemistry, and Mathematics as their subjects. Candidates appearing for the class 12th board exams in 2020 will also be eligible. There is No age limit will be there to appear for the exam.

As you have scored 66%, you are eligible for the test, no matter what your total score of PCB is.

I wish you all the best!

Hope this helps!