Here is an interesting chart from a 2007 Pew Research study related to average age and education level. While some years have passed since the study, I would imagine that not a whole lot has changed to reposition these groups on the chart.
Each circle represents a religious denomination. It also includes the categories of "atheist" and "nothing in particular."
Just a couple of personal observations: United Methodists are slightly above average with % of members being college graduates and we have one of the higher average ages. American Hindus are clearly #1 in both of these categories assuming you believe that a low average age and a college education are important for the future of your particular denomination.
One of the reasons aging denominations do not have a diversity of ages is because they are not connecting with their surrounding community. This raises all kinds of thoughts on how the church might reconnect with the community where it is located. It also leads us to think about how we might share our faith through our words and actions in more effective, creative, and consistent ways.