Hello Aspirant,

No, i don't think you can change your subject now after studying basic maths the whole year. I don't think even it's allowed to change now according to CBSE, but still to be very sure talk in your school and see if there's a solution.

And if you want to study maths in +2 you can go for Applied Maths, you're eligible for it but not the main core Mathematics.

Hope this Helps!

All the best!