Dear Vidhi,
Its good to know that you want to do bsc hons in maths.
I would like to tell you that its compulsory for you to have maths in class 12th if you want to further persue maths hons. Every college requires you to have studied maths in class 12th. Du requires 50%marks in class 12th maths so as to persue bsc hons maths. If you had maths along with commerce you can easily go ahead.
All the best.
I hope this was helpful to you.