It will not affect your admission process. But we would suggest you to appear for NEET 2020 before you decide to drop a year. You think you are not prepared for the exam but you actually do not know the level of your preparation unless you appear for the exam first. Based on your score and the cut offs after the complete process of Counselling has been over, may be you will have an idea of where you stand and how further you need to improve. This will give you an idea of the road map that you need to draft for yourself. Taking a break after 12th might not sound like a big deal now. But you need to remember that this means you will be always a year behind your peers. Taking a gap year and preparing for NEET will not affect your Career or admission process. But we would still suggest you to appear for NEET 2020 first before you take a call. If you have prepared for your Boards, the syllabus is the same for NEET as well. So you may as well give it a try because as of now, there is no upper age limit for NEET.