Hey aspirant

You can't get admission in NIT s with 55 percentile. So if you wish to graduate from IIT and NITs then you should take a drop. Work more, practise more questions, attempt mock test daily, do previous jee question papers, understand the pattern of exam, study according to weightage of chapters, thus you can score well next time. Keep a target of 97+ percentile for next time. Or if it is okay to graduate  from a government or private engineering college, then you should write othe engineering entrance exam so that no need to drop a year. If you have the threshold to work one more year then you should go or else you can go for private or government engineering colleges via other entrance exams.