The so-called youth is falling in love with someone when you are a teenager, and then finding that you can't get rid of her/his shadow throughout your life.
The so-called youth means thinking that you will remember that person for the rest of your life.
The so-called youth means that when you look back at your own youth, you will smile, frown, and say to yourself softly, there were times when I was so stupid, so passionate, so depressed or melancholy, when I wanted to be dissolute but unwilling to degenerate.
Then youth is dead.
Conception: