Murari, there is no upper age limit for NEET. So even if you have a gap year, if you meet the eligibility criteria for NEET, you can appear for NEET. You should be 17 years atleast by December 31st of the year of admission and you should complete your 12th with Physics, Chemistry, Biology and English as your core subjects. You should secure a minimum aggregate of 50% in Physics, Chemistry and Biology. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST. So if you meet this criteria, you are eligible for NEET.