I think this is the version you're looking for:

Enjoy Yourself (It's Later Than You Think)

  You work and work for years and years, you're always on the go
  You never take a minute off, too busy makin' dough
  Someday, you say, you'll have your fun when you're a millionaire
  Imagine all the fun you'll have in your old rockin' chair
  
    Chorus:
    Enjoy yourself. It's later than you think!
    Enjoy yourself. While you're still in the pink!
    The years go by, As quickly as a wink.
    Enjoy yourself. Enjoy yourself. It's later than you think.
  
  You're gonna take that ocean trip, no matter, come what may
  You've got your reservations but you just can't get away
  Next year, for sure, you'll see the world, you'll really get around
  But how far can you travel when you're six-feet under ground?
  
    Chorus
  

There's a (small) wav file of the Guy Lombardo version (1 verse & chorus) at Enjoy Yourself

Mick