You have made great strides so far in your weight loss. Just start riding slow and 25 miles is not that bad. If you cannot go that far at first, each ride after will get progressively better. In no time you will get to that goal, and start getting faster. Enjoy the ride.
Wow I too am training for a bike ride but mine is only 14 miles. How many miles have you gone so far at one time.?Is this training on a real or stationary bike? Would you like to become friends and encourage each other along?