Yes with a score of 580+/720, being from SC Category you may definitely secure a seat in MBBS at AIIMS Kalyani. You will perhaps even have many other options, including some of the Best Government Medical Colleges in Kolkata, West Bengal under 85% Home State Quota. As far as Preparation is concerned, I wouldnt say securing 580 or anywhere above 550 is Tough, but you need a Proper Startegic Preparation. Strategic selection of study material, strategic routine for regular preparation as well as a strong test taking strategy is what'll lead to your success.

For more information about NEET and Preparation Tips do follow the link below

https://medicine.careers360.com/articles/neet-preparation-tips