Hanging out with the younger set will either make you feel younger... or... older. From what I can tell, it's pretty much a choice as to which category you fall into.
This is true whether hanging out with grandchildren, or the younger set in church. But know this: if you want your church to get younger, you'll have to hang with the younger. And if you put your all into it, they will love you for it!
It is more blessed to give than to receive. Practice getting some blessing today.