Hello Tausif,

It is not only based on the 12 marks one can be allowed to give NEET. There are various other factors which are taken into consideration.

You must pass 10+2 or equivalent with Physics, Chemistry, Biology/Biotechnology and English as core subject in both Classes 11 and 12 from a recognized board

Other than this maximum and minimum age limit is also provided.As per the NEET 2019 eligibility criteria, a candidate is required to complete 17 years of age either at the time of admission or else on or before December 31, 2019. The candidates belonging to unreserved category must not be more than 25 years of age to fulfil the NEET eligibility criteria 2019. 

To get the proper details of each and everything regarding NEET, please follow this link.

https://www.google.com/amp/s/medicine.careers360.com/articles/neet-eligibility-criteria/amp

Good luck.