Not at all, class 10 math cbse paper is not tough at all if you practice from R.S. Aggarwal or R.D. Sharma.
I just solved R.S. Aggarwal fully and i score 86/90 in 2016 in my class 10 maths paper.
But keep in mind that you can easily solve only 90% of paper if you practice from R.S. Aggarwal.
And you can attempt 98% of paper if you have fully solved R.D. Sharma.