For me every course and every subject was tough when I used to study. You have a very good scoring in 12th and definitely think of taking up CA. All professional courses are competitive and tough, but not at all impossible to clear. Had the other 98 put the same efforts as the 2 did, results would have been 100%...isn't it? Study hard and have the determination, you will definitely succeed.
You can right away get registered with the institute for the CA course and do it paralelly along with your graduation. Good luck!