Yes. You can prepare for the NEET after 12th also, you can take a drop for preparation and join a coaching institute as a dropper or you can study on your own, howsoevr joining a coaching would be much better. If you are even a wee bit unsure regarding your selection or are unsure of sacrificing a whole year, you can join some other course as well and also keep on preparing for the entrance .
Howsoever my advice would be to go ahead and take a drop boldly and prepare with utmost focus and dedication. Do not ever get demotivated during your gap year. Immerse yourself in the preparation. Trust me, the preparation will teach you a lot more than PCB. If Medicine is your passion, this step will be worth it . All the best.