You are probably not going to be an overnight success with your podcast.  And, if you are trying to build a custom podcasting business you will likely be producing content for a year or more before you develop the confidence, professionalism and catalog that will get you noticed.  

But during this time you are going to be developing skills that will allow you to hit the ground running when companies start looking for podcast hosts.  And, you will be creating a network and putting yourself in a position to be taken seriously when you pitch ideas to potential clients.