First of all, great score. The second thing is that your category and state rank will decide that. As per the rules of KGMU , you need to have a rank between 88-496 if you are unreserved. The college merit list will be declared after the results. That list will decide whether you  will get admission in KGMU or not. Well all the best. I suggest you a link that will help you.

https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer

If you belong to Bihar and want to study in KGMC, you should try under All India Counselling. And in 2019, under State Quota, 620 was the cut off for KGMC under General Category. And so if you belong to General Category, then a seat in KGMC with a score of 620 is difficult. But if you belong to Reserved Categories, you do have fair chances. Having said that, this is based on 2019 data and cut offs change every year. Cut offs change every year depending on various factors such as no.of Candidates appearing for the exam, no.of Candidates qualified, top NEET score and difficulty of the exam. For a complete list of colleges that you may have a shot at, please use our College predictor: https://medicine.careers360.com/neet-college-predictor?icn=QnA&ici=qna_answer