The verse actually says, "that generation shall not pass away before they see My coming."  Forget how long a generation is.  Nobody knows and countless suggestions have been made as to the number, which is why you should KNOW that is not what is being said.  It means that someone or even several representatives of the last generation will be around to see His return.  Man's age span was reduced to 120 years.  1948 + 120 = 2068.  That then is the outer marker.  The Bible is replete with examples of God waiting until there were few remaining of a generation to witness the fulfillment of his prophecies.  I too thought it would be before now.  However, in light of the fact that He has not yet returned . . . and a parable saying we would ALL be asleep, I'm guessing we may have several more years before His return.  Oh, and it does not say He will keep us from tribulation.  Saints around the world experience that on a regular basis.  I believe He will keep us from His wrath and I pray THE TRIBULATION.

In Christ,
Melissa