People who were “good looking” when they were younger, how did you know you lost your looks as you grew older?

For example, being called good looking and having many girls go after you in high school/ university but the compliments stop as you go into your late 20's etc.

Could be vice versa too, being average in the past but getting more and more compliments as you grew older.

Which is better in your opinion? Looking good in the past or in the future?