CAT

I think, dropping in not a good idea. Atleast, you should try to prepare by yourself and for the self study purpose you can refer the famous author's books like
1. Quantitative Aptitude Quantum CAT Common Admission Tests For Admission into IIMs by Sarvesh K Verma (This is a popular book among Toppers, This is top selling book in India for CAT Quantitative Aptitude),
2. How to Prepare for Logical Reasoning for the CAT Paperback by Arun Sharma
3. How to Prepare for Verbal Ability and Reading Comprehension for CAT by Arun Sharma
A simple scheduling tip for you: depending on the breadth and depth of topic, assign 3 to 5 weeks per topic from now onwards. You should try to connect different topics and then work to simplify the connections using lateral thinking and common sense. You can refer the material to get an idea of the understanding required. Please note that you must focus on Concepts first rather than problem solving. According to me, you should give the exam this year because by doing this, altleast you get an idea that what type of questions would be asked.

Hi Neha,
Quants is a subject that would ask you for your patience and hard work. The only and the best way to prepare is to practice as much as you can. Try solving past papers and also give number of online mock test. Google out shortcuts for certain chapters. I would say along with hard work you would need to work smartly. Try figuring out which chapters has the highest weightage and focus more on the same and practice more sums. Practicing more and more would not only help you increase your speed but also would help you to boost your confidence along with it. Keep a target w. r. t. time and try solving those number of sums within the time limit. Remember do not spend much time on a single sum as you would lose some for the rest of the sums. For other subjects you need hard work. And mainly do not wait to solve the papers until you complete your syllabus, start solving the paper and attempt entire section irrespective of you knowing the chapter or not. This would help you to understand as to how much you know of the portion you have learnt and how much can you solve without knowing the same. Further, you should keep in mind:
A. Entrance Exam
B. GDPI
For GDPI there are certain do's and don'ts mentioned in this article link below so kindly refer to it:
https://www.shiksha.com/mba/articles/mystory-jill-shah-don-t-be-afraid-of-making-mistakes-blogId-17567
All the best.