Dear Niteen ,

I hope you are doing well !

Yes ,you can appear the 12th CBSE board last time because CBSE board only gave 3 time for re appear the exam so kindly study hard this year and try to pass the exam .Dont worry you get successes only think positive.

First of all collect 4-5 years previous years questions papers and try to solve from lower to higher level or you can to what you know in this way your confident level will increase and you motivate towards to solve another solve questions .

I hope it will helpful

thanks