Hi soumya170293,
Each year, the new Official Guides that are released have many of the same practice questions as the versions from the prior year. Based on your studies so far, you won't see that much 'new' material if you purchase the GMAT2021 books, so you might find it more worthwhile to work with some new, non-print, practice materials
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied? How many hours do you typically study each week?
2) What study materials have you used so far?
3) On what dates did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your overall goal score?
5) When are you planning to take the GMAT?
6) When are you planning to apply to Business School and what Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich