New to the Idea of Yoga...?

I have never done Yoga. I think it sounds & seems fascinating & exilerating! I would love to try it! My problem? well I am overweight (obese) and not co-ordinated, so I am too ashamed & too afraid to join a class or ask a class to help me...hmmm I am working on losing the weight (its a battle)...but my question is...Does anyone have any suggestions, ideas, or advice to give an out of shape, obese, uncordinated female? I would like to one day be in a class or something, I want to learn yoga, just don't really know where to start right now? thanks so much for your help :)