Hi

You don't need to worry about your class tenth percentage or class 12th percentage as these are not considered for checking your eligibility for CAT examination, what matters is your graduation that is BBA in your case .

CAT eligibility criteria says that:
To be eligible for CAT ,
you need a  Bachelor's degree with at least 50 per cent marks or equivalent CGPA . SC/ST/PH students need only at least 45 percentage in Bachelor’s Degree in any discipline to be eligible . Candidates who are in the final year of their graduation are also eligible for CAT examination.

So, irrespective of your marks or percentage in your class in 10th and 12th if you get at least 50% or at least 45% in your BBA if you belong to SC ST or PH then you are eligible for CAT examination

For detailed information go through
https://bschool.careers360.com/exams/cat

Now that,
You are eligible for CAT examination you should focus on your preparation but before that you should know its examination pattern which is provided below

PAPER PATTERN
IIMs officially don't release cat examination pattern, expected CAT 2021 pattern is provided below:-

-)CAT 2021 will be of 2 hour duration
-)it is conducted in computer-based mode.
-)In cat 2021 , there will be a total of 76 questions - 54 mcqs and 22 non - mcqs
-)The complete paper will be divided into three major sections, which are listed below along with number of questions they have:-
*QA i. e quantitative Ability :- it will have 26 questions in total (18 mcqs and 8 non - mcqs)
*DILR i. e data Interpretation & Logical Reasoning :- it will have 24 questions (18 mcqs and 6 non - mcqs)
* VARC i. e Verbal Ability and Reading Comprehension :- it will have 26 questions( 18 mcqs and 8 non - mcqs  )

-)There's 40 minutes for each section .

Marking scheme:-
-)3 marks is awarded for every correct answer
-) -1 marks for every wrong answer in case of mcqs
-) no marks deduction is there for wrong answers in case of wrong non -mcqs .

To start your cat preparation, first of all go through its syllabus at

https://bschool.careers360.com/articles/cat-syllabus

Top books which you can follow for CAT are listed below section wise  :-

QUANTITATIVE ABILITY

-)How to prepare for Quantitative Aptitude for the CAT by  Arun Sharma:-

*it is the best  book  for your Aptitude for your cat examination .
*it covers all the topics according to your cat syllabus.
*it has elaborative examples so that it's easy for you to understand them .
* questions are divided into 3 levels of difficulty

DATA INTERPRETATION AND LOGICAL REASONING (DILR) :-

-)Logical reasoning and data interpretation for cat by K. Sinha Nishit:-

* the best thing about this book is it starts with your fundamental and basics and then goes to advanced level too, you get each topics with explained examples .
*it has questions divided into three difficulty  levels, so that you can start from basic and move ahead step by step

-) how to prepare for data Interpretation for cat by arun sharma :-

*it has  strategies and concepts which you need  to solve questions  accurately and quickly.
*it has exercises which are designed in a manner to help you boost your logical thinking etc.

VERBAL ABILITY AND READING COMPREHENSION

-) word power made easy by norman lewis:-
*it is one of the best books that you can get for improving your vocabulary .
* it helps you in learning correct usage of words etc.
* at the end of each chapter you get review exercises

-) mastering the verbal ability for cat by ajay singh:-
*it has more than around 200 passages for your practice .
*it also contains test papers of other B-School as well, etc.

-) How to prepare for verbal ability and reading comprehension for the cat by arun sharma and meenakshi upadhyay:-
*it is written in a very lucid manner.
* it has past year question papers analysis .
* you get topicwise segregation  in this book along with mock papers for your practice.

For detailed information go through our page the link for the same is provided below

https://bschool.careers360.com/articles/best-books-for-cat-preparation

*Make a routine and religiously follow it as it will help you to utilise the time in the best possible way and  avoid procrastination and laziness .

*Keep short breaks of 20 to 25 minutes after every 1.5 to 2 hours between your studies in your routine .Half of the time of your studies must be for practicing questions

* Plan your studies, and set daily, weekly and monthly goals and meet them without any fail.

*Solve previous  year question papers of CAT :-it will let you know the examination pattern, type and difficulty level of questions, also concepts behind the question often gets repeated, so you should definitely solve year papers . You can get cat previous year question papers at https://bschool.careers360.com/articles/cat-question-papers

*Once you are done with complete CAT syllabus then go through CAT mock test papers , it will let you know your preparation level and and weak areas so that you can work on them and perform well in your examination

For detailed information go through

https://bschool.careers360.com/articles/how-prepare-for-cat/amp

Thank you