Hello Abhirup Mukherjee

Yes , you can definitely pursue diploma . Actually Your 10+2 qualification is not required when it comes to pursuing diploma as Diploma course can be pursued right after class 10th, so it really does not matter whether you have passed your 10+2 with commerce or any other stream as to be eligible for Diploma you need to be just 10th passed .
So yes, you are eligible for Diploma even after pursuing 10+2 from commerce



Thankyou