While you say that you are in 10th, just concentrate on following few tips and you will be alright till your boards:
1)Never fear or hate exam and be confident
2)Prepare a good time table
3)Select a proper atmosphere for studying
5)Make notes while studying
6)Sleep well and Eat well
7)Write and Present well
8)Believe in yourself
This will surely help.
And about CA (chartered accountancy) theres only one institute offering certification in CA. Log on to ICAI.org and you will get all the details about the course,syllabus etc.
But before you do that surely you would want to read more on CA - career map, scope, opportunities, remuneration, benefits etc- so log on to http://www.youngbuzz.com/careers/careerdetail/chartered-accountant
Hope this helps.