Exams do not have to be our enemy. The deciding factor in whether an exam is an enemy to us, or “on our team”, is how well we know the answers to the challenges and questions involved in the exam. For the GMAT, do you feel like you already know all the information that is required for the questions? I guess the only way to be able to make a judgement of this is by doing a prep run of the exam, or a mock exam as many people call it. This will show you just how good your knowledge is at the moment, and it will also show you which areas you need to give more focus to because certain questions will be too hard to answer (that is the part that shows you this is a hole in your knowledge).
To make sure you get the best chance of doing well on the GMAT mock exam attempt (if you decide to do one) then a good option to take now would be to buy the best GMAT prep course that is currently available. That book will give you a great foundation to study from, and will be a key reason that you score high on the exam.