In Step 1 on your Start page on the left side you'll see a "Track Weight" button. Under it is a link to edit your goals. Click there and from that page you can change your starting weight.
Hope that helps,
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford
"No matter how slow you go, you are still lapping everybody on the couch."