I'm a Masters student currently deciding which area to focus on. So far, my primary interest has been $C^*$-algebras and operator algebras (I already have some knowledge of $K$-theory for $C^*$-algebras and Hilbert modules), but I always had some interest in geometry. When I learnt about the Gelfand Representation Theorem, I thought there was a chance to mix both interests.
I tried to read Alain Connes' Noncommutative Geometry and realized that I was missing lots of prerequisites. I'd like to have at least a broad enough picture of this area to determine whether I like it or not. What is the minimum I should know before I can do that?