Hello Kuldeep,

It is also advised to have an early start to every preparation. The more time you have in hand for preparation the better the outcomes. So, in my opinion, it is better to start in class 11th so you have enough time to grasp the concepts memorize them and practice question papers for revision.

There are many Institutions available these that provide guided education and required materials for preparation of competitive exams and board exams as well.

But at the end of the day, it all depends on you and your capability to grasp. Many students take a gap year to prepare for competitive exams so that they get a decent rank and that is also a great approach.

Good luck !