I've had enough

Ok I've had enough. I went for a walk today and I walked .68 miles and it took me 30 minutes. Talk about a fat man. I weigh about 300 pounds now. When I was walking before I had knee surgery on my right knee I was walking a mile in about 20 minutes, Now I can't even walk 2/3 of a mile in less than 30 minutes. It's time to get my butt off the couch and start moving. I plan to work up to that 20 minute mile this month and I am setting a goal right now to walk 100 miles in the month of October. I actually started last night when my wife and I walked about 1.25 miles with the dogs. Not sure how long that took us cause I didn't time it.