what would be my rank if I got 120 marks in jee advance 2021and which college i would get
As far as jee advanced is concerned every year the total marks changes and accordingly the ranks. So, nobody can predict your jee advanced rank until and unless the total marks is known.
Still if i consider 360 marks as a barrier then if you score 120 marks out of it you should be able to grab around 8-9k rank but kindly note these are only my predictions and these will vary definitely.
So, i would recommend you to not to think about your rank and be focussed to give your best shot at the exam.