Overweight people can certainly do yoga! It doesn't matter how old or young or what physical shape you are in, yoga is for everyone. There are quite a few overweight people at my studio, I do bikram, the hot yoga. And seriously some of them can kick my butt. We have some people in their late 60's and they are doing so good. Not to mention the wonderful mental benefits.

If you want to give it a try, I say go for it! Nothing to loose, it's also very non competitive. My sister just started coming with me, she is overweight, but she's absolutely loving it.