I was young and foolish then; now I am old and foolish

It is better to be a young June-bug than an old bird of paradise

Too young to care; Too old to change.

That's the trouble with you young people. You think because you ain't been here long, you know everything. In my life I already forgot more than you ever know.

When you're young, the question is "What can you do for me?" and when you're old the question is "What can I do for you?"

As we grow old the vigour of youth is exchanged for life experience and wisdom.