hey vaishali, you have a good amount of time left for aiims preparation but if you are truely determined to crack it than first of all you must follow a proper routine and strategy only than you would be able to crack it.Many people starts preparing for it 4 years ago but some of them do not follow the routine of study time and revision and they had to deal with difficulties afterwards no matter how much hours they study.So i would advice you to study 4 hours per day for a better preparation.