"while we're young and beautiful"

It means that you gotta enjoy living young and beautiful. Enjoy the little and big things while you can. It only happens once in your teenage years, but when you grow old you tend to miss what you love to do when you are young, but it doesn't mean you can't do it anymore.

 There are things that you would be able to do and some you won't be able to try anymore.

 So, better enjoy what you do at this time, because great possibility that you only get to watch the next generation of teenagers doing the stuff that you do during your years.

 And all you get to do is just SIT and WATCH. 

It's much better to do the things that you can't do , so that when you grow older you 

get to watch your children or grandchildren and say "I used to do that, It was so much fun" and reminisce the days that you use to do those awesome things. 

___I DON'T KNOW___WHY I CAME UP WITH THIS TOPIC.