How to convince parents for dummy school in 12th

I am currently in 11th and am planning for dummy school in 12th, but the problem is that my parents (especially mom) would be against it. I am a commerce student and am preparing for law but don't get enough time because of my school which is for 6 hrs. If I do dummy schooling then I'll get enough time to prepare for law, prepare for boards and also for my hobbies. As I am currently a cbse student and will switch to a state board in 12th, school will be way easy for me anyways so I don't need to waste my 6 hrs. Even if I give all the logic and reason my mom would still be against it. Please give me some suggestions on how to convince my parents for homeschooling. Thank you