Hi kritinbansal,
It looks like yashikaaggarwal has answered your particular question. In regards to when you should think about scheduling your Official Test appointment, it's worth noting that many GMATers spend 3 months (or more) of consistent study time before they hit their 'peak' scores - so if your studies followed a similar pattern, then you would be taking the GMAT in the middle of September. That is a "busy" time of year for the GMAT, meaning that if you want to take your Exam at a Test Center, then you might find it difficult to schedule a specific Day/Time that suits you best (IF you wait until it's too late - such as late August or early September - then you might not have that many options). This is meant to say that if you have a specific appointment time in mind, then the earlier you try to book that appointment, the greater the chance that the specific slot will be open. You can also pay to reschedule that appointment, if you find that you want more study time (but there is a fee - and the fee increases the closer you get to your appointment date).
From your other posts, it sounds like you're just beginning your studies. As such, it would be a good idea to take a FULL-LENGTH practice CAT Test; you can access 2 for free at
https://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 3.5 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have that Score, 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 apply to Business School and what Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich