There is nothing mandatory to go for the all india quota counselling only. All india counselling is conducted for the admissions in govt. medical and dental colleges across india. If you have scored 500+ marks then you can go for the all india counselling and you can get the seat in the medical or dental colleges. For the rest of the colleges such as deemed or private and govt. medical or dental colleges in the respective states the counselling will be counducted by the state authority. The marks range in the state quota counselling is low as compared to the all india quota seats. So choose carefully that for which counselling you want to go for. If you very good marks in NEET then only go for the all india counselling otherwise you can go for the state quota counselling. Go through the link below to know more about the counselling proess and admissions.

https://medicine.careers360.com/articles/neet-counselling/amp#referrer=https%3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s