sir , is it would be better to kota , rajastan to join iit institute like bansal, allen in class 12^th then to go as a dropper ?

You should start planning your preparation the year you’d be appearing for Class 12 exams rather than drtopping a year and spending it all over preparing for IIT JEE when you have an entire year. Though, it would need you to balance the school as well as JEE preparation studies all together, but it is this balance that would bring the best out of you. Manage your time well.

All the best.