Good start!! I'm glad to see Beth and Larry respond to your post. When the issue of weight comes up, these people have some of the best advice and encouragement on the board. What makes this place unique is the fact most of us have been in your shoes. In fact, I lurked around on the site for about a month before posting my results and jumping into the message board! I can tell you that it will take about 3 months to a year to do the WOD as prescribed, but don't be discouraged!! It took time to put on the weight and get where you are now, it'll take time to get where you want to be. The hardest thing to do is start, and you've accomplished that already. The WOD will build mental toughness as well as physical strength.
Finally, enjoy the board. There are some great people here with great knowledge and senses of humor!