In my late 30s and realized how bad of shape I had become. October of 2014 I purchased c25k. Had a few stops and starts along the way. Finally really started working at it hard this February. Well I have lost 40lbs. Did change my diet also. Ran my first 5k this Sunday and just totally shocked myself with a 26 min time. Already signed up for a 10k. If a former couch potato like myself can do it. So can you!!