MadCityCyclist

Ewok, that's probably the best choice you could make, just make sure all the components (especially the brakes) are in good working order. Build up your stamina at a comfortable pace and use the time to find a bike to upgrade to later on. One advantage to shopping at a bike store vs. a big box retailer is that the local bike stores will let you test ride their bikes and they should be able to give you knowledgeable advice on seat height, what type of bike would work best for you, and what frame size (based on your height) you'll need.

I started out commuting on my old college bike, a run of the mill mountain bike. Rode it for two years, during which time I researched the different bike types (hybrid, comfort, city, cross, etc.). By the time I decided to upgrade to a more serious commuting bike, I was able to walk into the bike stores and have some good discussions with the various salespeople about the bike types, how the bike would be used, and what the best bike for the local terrain was. I also had a much better idea of what bikes were the best value for the money, and in the end I was able to make a far smarter and better purchase decision by riding my old mountain bike first.