Is dropping a year for iit jee a good idea

It depends from person to person. I personally believe that you should definitely drop for JEE. You know you are afraid that you may lower your marks, which has a very low probability of happening. But if you drop and do well next year, you could easily pursue CSE, which you have always wanted to. A

no you should try for state government or private colleges.From next year IIT jee pattern is also going to change.you can also give exams conducted by some of the private colleges to get branch of your interest. wish you luck