Couch-to-5k (C25k) is fabulous. It's how I got my start...then I continued very slowly building my miles. I've never had any serious sidelining injuries in 3.5 years by doing this (and have logged nearly 1700 miles since the start of the year). My best friend is not so cautious and has had several stress fractures and is now battling plantar fasciitis. She is the most bull-headed person I know and pays the price. Too many miles too fast is recipe for injury. Take it slow, pay attention to your body, and you'll be amazed at what you can work up to.