Physics tutor for IIT JEE with more than 15 years experience and having produced ranks 26, 83, 133, 198, 298, 483 and many more.....
At the moment you should concentrate on board exams and prepare your XII class syllabus in such a manner that you cover all the topics from point of view of JEE as well. And when board exams are over, during that time you can revise your XI class syllabus. So that your entire syllabus is revised before taking the actual JEE exam. Hope to solve your confusion about studies.