Hi Moitri,
First of all, let me tell you that the difficulty level of paper depends upon the mindset and preparation of the student. Let it be Bengali medium or any medium students, the exam level is same for all. Even in order to break the language barrier, the entrance exam NEET is conducted in Bengali, Tamil, Telugu etc. language as well along with Hindi and English.
So align towards your goal and stay focused, believe me any type of language will not be a barrier for you as long as your basic concepts and fundamentals are strong of that particular subject.
Regards to one of the future doctors!
All the very best.
Cheers!