Hello Aspirant ,

Yes , It is possible for you to repeat class 12 again after you fail your boards exams and that is exactly what most of the students do after failing , you will have to start your class 12 from scratch again and you will be studying with your juniors.

I would suggest you to prepare with hard work this time and it will be easier for you as you already have a good enough Idea about class 12 syllabus and examination .

Hope this helps.