Hey dear, if you see the last year's cutoff which went very high that even students getting 500 marks found it hard to get govt. Mbbs college. So, with 520 marks and being a obc candidate you will have a clear chance under state quota for sure. But, i am not sure about the all india quota seats, still you are getting good marks, do attend the counselling , may be you have some chances if cutoff falls less. For more information regarding marks and ranks go through this link:

https://medicine.careers360.com/articles/neet-result-marks-vs-rank

You can also use college predictor through this link:

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