Too Long; Didn't Read
There is no one path to becoming a product manager. Product management is a position with a huge amount of variance. Some pms start as developers, some come out of mba programs, some start as product interns and work their way up. The more skilled and knowledgeable you are in each discipline, the better you can interface with your counterparts. The true art of the product manager may not be a popular one but here it is: A product manager should be able to create the product in a microcosm.