My dear friend It is one of hardest exam in India and you need to dedicate an entire year to crack this exam and is not an easy job to eligible in IIT you should clear JEE MAIN and ADVANCE then you may apply for IIT. And Now your answer Yes you make take a drop for preparation for IIT and if you think you are not able to crack the exam then you should take another private engineering college but make sure what you want to do because of at the last the decision is your which decide your future study.

All the best