The median age of people in the United States is 38 years old. That means there are roughly the same amount of Americans under 38, as there are over it. Most would consider 38 to be quite young. So you might as well get used to it. The country skews young. In fact, it always has. In 1960 the median age was 30.
Instead of resenting the young for their independence, energy and freedom, embrace them. Be the person you would like them to become. They still have many choices to make in life. Show them what the right choices look like.