I want to repeat for jee mains and other competitive exam.i want to know some suggestions and opinion.pls can anyone help me

I would recommend you not to drop yours year as it is still not sure that you will able to get top scores in next year JEE or not. I suggest you to join some university and side by side prepare for your JEE, also the first year subjects will cover most of the syllabus of JEE which will help you crac

It is always good to take a strong opinion on repeating a year. I would suggest, join a reputed coaching institute like Allen, FIITJEE, Bansal or more, and prepare hard for a year. Get into an IIT mostly. If not, NIT is definitely a back up. Prepare well, Good Luck :)