To be able to appear for NEET, you should have completed your 12th or should be appearing for 12th exams and the result should be out atleast by time of admission and counselling. Even if there is backlog, the goal should be to be able to clear the subject atleast by the time of counselling and admission. You should meet the aggregate criteria atleast by the time of counselling for you to be able to participate inNEET counselling and join if given a seat. Now, with a backlog you are eligible for NEET but your admission is subjective based on the result of this backlog.