Hi AaravKapoor,
From your post, I assume that you are trying to decide between the GMAT and the GRE. Most Schools will accept either Score as part of the application process, but you should check to make sure that the Schools YOU plan to apply to actually accept both (as it would be unfortunate if you took the GRE only to discover later on that a School you were interested in would not accept that Score).
Since it sounds like you're just beginning your studies, then it would be a good idea to take one FULL-LENGTH practice GMAT and/or GRE Test; you can take 2 practice GMATs for free at
www.mba.com and two practice GREs for free at
www.gre.org (both websites include some additional free practice materials). If you want to do a little studying first, so that you can familiarize yourself with the basic content and question types, then that's okay - but you shouldn't wait too long to take that first test. That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. Each Test takes about 3.5 hours to complete, so make sure that you've set aside enough time to take the Exam in one sitting. Once you have those scores (either Exam or both), you should report back here and we can come up with a study plan.
I'd like to know a bit more about your timeline and goals:
1) What is your goal score?
2) When are you planning to take the GMAT?
3) When are you planning to apply to Business School?
GMAT assassins aren't born, they're made,
Rich