You can apply for admissions in a NIT. Most NITs are on par with IITs and it is a better alternative than wasting an entire year and reappearing for JEE Main next year in the hopes of gaining admissions in an IIT.
All of these institutes produce exceptional professionals every year. You could be one of those professionals if you don’t lose time and apply to these institutes.
Although JEE is the most popular Entrance Exam in India, but the candidates must not under-estimate the other Engineering Exams that hold the worth of National Importance too.
If you don’t get seat in any NITs, IIITs or GFTIs, then you may go for these colleges as they are truly luxurious and best suited with the IITs and NITs standards.
If you are firm in your resolve to join an IIT, then you can reappear for JEE Mains. You are permitted to attempt the exam twice.