Greetings Vivek!

Hope you're doing great.

Well, the number of applications for CAT in recent years has been around 1.8 to 2 Lakh. Of course the number of candidates who actually attempt it will be lesser than that. But not all are serious aspirants. Your actual competition will be 30 to 40 thousand candidates for almost 20 thousand seats in the top 85 colleges. One thing should be kept in mind that is, the total number of aspirants who fill up the forms don't appear in the examination hall. Hence, the selected number of students are serious for this test which I've mentioned above. So, if you plan your way and work hard then you can surely score pretty well in this examination.

So to kickstart your preparation, firstly take a diagnostic test for CAT(or solve past year paper) to know where you stand in terms of level of your Maths, English, LR/D I. Its just like pre-board where you get to know your strong and weak areas and work upon them by the time before your mainboards. Prepare with of zeal of getting into IIMs. The competition is stiff but every year's thousands of student make their way to management institute.

Hope things are clear now. Do reach out in the comment section below if you need any help. 

All the best!

Cheers!