I can attest to that. When I began, I did it all wrong. And bicycling is still the transportation choice for most people on the planet. THE BIKE Most importantly, get a bike that suits your needs. Try a variety of bikes before you buy and ask the shop to make adjustments for your size and body type.
Mountain bikes are fine for dirt trails but can be heavy and inefficient for commuting.
Look at hybrid bikes or road bikes for the best balance between weight, comfort, and durability. Narrower, smooth tires offer less road resistance. Consider comfortable riding clothes and a change of attire at work. Neoprene booties which fit over your shoes keep your feet dry in the rain. For cold weather, thin layers keep you warm and can be removed easily.