If you have studied properly as expected from an average student then you can pass board even if exam comes a little tough.
So don't worry about difficulty level , go study and give your best and you would surely get good marks as exam do come difficult sometimes but not that you need to worry to get passed.
Study from ncert properly
Also do last year papers and see which topic you arr weak in and read it again.
Hope it helps

According, to CBSE boards exam 2017  Paper was lengthy and tricky.

Mathematics was tough and chemistry was easy.

 

You should not loose hope. Be motivated and determined.

Yes, you can pass your 12th exam but you need to work hard to score good marks.

 

Complete your syllabus. Work on your basics. Refer previous year papers. If you are weak in physics and chemistry work on these subjects. You can make your important notes which will help you in revision as well. You can consult with your teachers they will guide you. You can also join study group.

 

All the Best!!