Don't let your weight keep you from biking. As others have said, plenty of people are overweight (me included). I have foot, knee and shoulder problems that prevent me from doing most common forms of exercise, which is why I started biking. I'm heavier than you are, I ride a Trek 1500, and I put on my Lycra shorts (that make my legs look like sausages!) and head out to the bike paths. I am in deplorable physical shape, but I can ride my bike for an hour on a beautiful day, enjoying the beauty of the bike path and have a glorious time. Even when I seriously over exert and think I won't make it back to the car, I still love my bike! The beauty of biking is that those of us who are not athletes or have "issues" can still enjoy riding a bike. For me it is more about the enjoyment of the ride. The exercise from the experience is an added bonus. Get out there and enjoy yourself!
The pessimist complains about the wind. The optimist expects it to change. The leader adjusts the sails.