Hello Guys,
I am currently studying Bachelor of Management Studies in India which is a 3 years program.
Are there countries with well known B-Schools for Finance Specialization which will accept 12+3 years of education?

Canada has been covered somewhat here in the past:

https://find-mba.com/board/americas/is-15-years-of-education-a-problem-in-canada-now-51363

But in all honesty there's no one country where all the business schools will be ok with this. You'll have to go on a case by case basis, researching the schools that you are interested in particularly.