With a 20 percentile in JEE Mains and an EWS certificate, getting admission to top government colleges like RTU Kota is difficult. But you still have chances in private colleges affiliated with RTU for branches like Computer Science. These colleges also offer seats through management quota or direct admission. You should also apply through REAP (Rajasthan Engineering Admission Process) where some low-rank students also get seats. Contact colleges directly and keep documents like 12th marksheet and EWS certificate ready.