So, where do I begin? I have a current interests in going into Algebraic Topology and I am currently learning about Point-Set Topology and Abstract Algebra, which are pre-requisites to Algebraic Topology. After talking to a professor, he recommended learning some Differential Geometry, but I think this requires some knowledge of Differential Forms first (not 100% sure). So can anyone recommend me in a good direction towards Differential Geometry? What should I know before pursuing this topic? I'm guessing some vector calculus like Green's/Stoke's Theorem and what not. Any suggestions or advice is greatly appreciated. Note: I noticed that a lot of Algebraic Topologists also know a lot of Differential Geometry too, which I know is not a coincidence.