I would rather take the GMAT when i have the most time. Because scores are valid for 5 years, its best to take the GMAT when you have the greatest opportunity to do well. If you have time now, you should start prepping now .There is really no one answer to the question "how should i prepare". There are so many factors that go into a good score. All you can do is to read several experiences and see what advice suits you best. Remember, you could score a 750 after studying for a week or after studying for a month or after studying for three years. The length of time does not matter. Where on the talent scale are you in GMAT Math and GMAT Verbal?
Take a diagnostic test (or two). That will help answer that question. Whether you are eventually able to consolidate on your strengths and minimize your weaknesses is where its at.
Discipline is often the most overlooked aspect of GMAT prep. So , if you find it difficult to stick to a schedule , you should consider hiring a private tutor or enrolling in a classroom or online course.
Incidentally, typing in caps and using lot of smilies will not cause a reader to read more carefully. It is also considered "shouting". Also, when you post, please make an effort to show what steps you have taken to solve the problem. There are many quality posts here that talk about GMAT preparation. Please make an effort to read through them.
Hope this helps
thanks
Praetorian