Hi singhdhiraj,
Since it sounds like you're just beginning your studies, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can download 2 for free from
www.mba.com (and they come with some additional 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 initial CAT. 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. A FULL CAT takes about 4 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
While 3 months is a good amount of time to study for the GMAT, your particular needs might require more or less time than that (and you may or may not need to invest in a GMAT Course). The 700+ score is essentially the 90th percentile, meaning that 90% of Test Takers can't score at that level regardless of how many times they take the Test. This is meant to say that you might need to be a bit flexible with your plans (and you might end up needing to push back your Test Date).
1) When are you planning to apply to Business School?
2) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich