Hi there, 

Thank you for posting your query on our platform.

If you are currently in Class XII then you can surely complete the syllabus of Class XI easily. What you must do is add a few extra hours in your study schedule and devote that extra time solely for the preparation of Class XI.

In the mornings you can study NCERT of biology and do physics and chemistry alternatively on days. You don't need to study Physics and Chemistry from scratch just get acquainted with the formulas and start solving previous years questions right away. When you are done with previous years questions, start solving DC Pandey Arihant book for Physics and Vibrant academy's books for Chemistry.

That'd be enough.

Please feel free to post any further questions on our platform.

Wishing you luck!