Repeating 10+2 once again can be a waste of time for you. If you wish to go for the engineering, then you can opt for the NIOS on demand examination and can only pass the paper of Mathematics from NIOS. As NIOS results are admissible for the admission to engineering courses in India, you will thus be eligible for the engineering course and your time will be saved.

If you want to go for the regular mode of 10+2, then you have to contact the school and then you have to know about the rules and regulations to do so.

For more information regarding the NIOS consider the link below:

https://school.careers360.com/exams/nios-class-12

I hope this helps. Wish you a great eve!