Hi Sana,
You might receive more of a response if you post this in the 'Study Buddy' forum here:
https://gmatclub.com/forum/gmat-study-buddy-4/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.
Early last week, GMAC made a formal announcement defining some changes that will be taking place to the format of the Official GMAT (beginning April 16, 2018). These changes primarily impact the overall length of the Exam (meaning the number of questions in the Quant and Verbal sections as well as the amount of time that you’ll have to complete each of those two sections). In theory, a shorter Exam could make it easier for a well-prepared Test Taker to score higher. While the new Official practice CATs in the new 'format' don't exist yet - there are some 3rd party CATs that have already been adjusted to the new format, so you should plan to take one (so that we can get a better sense of how you perform under these new conditions).
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?
3) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich