Personally I think the opposite is true to some degree. Age does not guarantee that you are a rational and well informed citizen. I've also read numerous articles about how young people are more tolerant (gay marriage is a good example), moving back into dense urban areas (causing less sprawl and a renewed interest in better public transport and urban planning), and willing to at least admit that major challenges like anthropogenic climate change are real. Society can learn from people of all ages, but often the enthusiasm and free time of youth is what is needed to drive real societal change.
I'm not sure what that has to do with age of responsibility? The statistical facts are there to show that people under the age of 25 have generally impaired judgement compared with those over. (Among other things that's why you can't rent cars until 25.)
