Hello souvik,

Hope you are doing well.

As per your question, you can do bsc in mathematics as you have metioned you favorite subject, so accordingly bsc would be best for you. Also don't worry for your minor ups and down in your score or rank because PWD has its seperate category in which you will get some kind if relaxation in your merit.So you just need to enroll into that admission procedure, that's it.

Hope this information helps you.Thank you