Welcome to the forum, I'm new here myself and found that its a great source of information and encouragement!

Do not, in any way, be embarrassed about being larger and cycling. I think when most people see someone larger (or older) than themselves cycling, running, etc, they are impressed and encouraged to do more themselves.

BTW, my sister has a similar body style, and from this thread, I'm going to ask her about the thyroid and glucose intolerance issues mentioned - I know there is some family history of thyroid problems, and diabetes in older years in our family is the norm...

And I second the warning - cycling is addictive. I think about riding all the time, I can't pass up going into a bike shop just to look around, and I'm constantly checking the weather to plan the next nice day for riding. Oh, and I do ride several times a week too.