It's a difficult question to answer because it requires an assessment of your abilities, which no one on this board can provide. Only you know your strengths and weaknesses, and can determine how much time you'll need to study. I would advise taking a prep course and practicing as much as possible. I found the practice tests to be very helpful. The more you take them the more you'll see patterns and start to anticipate the correct answer.
You have plenty of time, why not start practicing now?