You need to get very excellent marks to get into IIT Bombay's MSc Physics programme. The best scorers are given admission to the programme at IIT Bombay's UR seat. In order to get a seat in the UR category, I would advise you to aim for a rank of roughly AIR 1-70. For the best chance of getting into IIT Bombay, try to earn at least a 60 on your IIT JAM physics exam. Moreover if you don't have confidence in your preparation level for 2023, then going for 2024 is always a great idea!

Till then keep practising and working hard! Hope I have answered your question. All the best!