Hello Suraj,
The best course to take up after 12th will be CA or Chartered Accountancy, as after this you can set up your own firm and work their according to your wish and time. The best thing about the CA course is you do not necessarily have to be from commerce background only to pursue CA.
Also, the career opportunities are great and you can make handsome money if you work hard.

Hope this helps,
Good Luck!

PS: feel free to ask any queries.