Hi browniidgirl
Welcome to the forum. The short answer is, technically yes...you could lose 100lbs in less than a year, but that will require a steady 2lb/week loss. In the beginning it will come of quickly, but a sustained weight loss of 2lbs/week will require diet and exercise. You can do it, but you'll have to work for it!!

Like kiwigirl said, just get started!! No matter were you are in a year, it will be a better place than you are today as long as you start! Best of luck!!