Hi

No, even if you do 12th again your old 12th and btech certificates will be equally valid,  certificates once earned is earned, its not like if you get enrolled in 12th again, your BTech certificates will become invalid, it will still remain valid so  don't worry.

If you are planning to give 12th again to be eligible for Neet, I will suggest you to give NIOS on demand examination for 12th   with all the  5 subjects including physics ,chemistry biology and English and for the 5th subject you can choose any subject of your choice like Hindi ,Sanskrit, maths or any other subject and after passing,  if you fulfill the  percentage requirement in PCB i. e

50  % in aggregate of PCB  i.e Physics, Chemistry and Biology/Biotechnology  in 12th examination  if belongs to general category , or   at least  40%  in aggregate of PCB if belongs to  Obc/ Sc /st category  , or at least 45 % in aggregate of PCB in case of general pwd candidates to be eligible. You should also pass in English.

If you fulfil this percentage requirement in PCB,  then you will be eligible and can get admission in MBBS on the basis of marks/rank obtained by you in the Neet examination

For detailed information about neet examination eligibility go through our page for which link is provided below; -

https://medicine.careers360.com/articles/neet-eligibility-criteria

Thank you