Was the temple built in 46 years or was it 46 years old during Jesus' time? I stumbled on this verse again and would like some clarification:


  Then said the Jews, Forty and six years was this temple in building, and wilt thou rear it up in three days? John 2:20 (KJV)



Was the temple 46 years old at that time?
Was the temple built in 46 years?


If it's the second option, how could it be true that the temple took so long to build? Were they short of labour, money, etc.?
It means it took that long to build. This is apparent from the fact that they were challenging Christ's claim that He would build it in three days, when it's taken 46 years of work thus far.

From Barnes' Notes on the Bible


  Forty and six years ... - The temple in which they then were was that
  which was commonly called "the second temple," built after the return
  of the Jews from Babylon. See the notes at Matthew 21:12. This temple
  Herod the Great commenced repairing, or began to rebuild, in the
  eighteenth year of his reign - that is, sixteen years before the birth
  of Christ (Jos. 'Ant.,' b. xv. Section 1). The main body of the temple
  he completed in "nine years and a half" (Jos. 'Ant.,' xv. 5, 6), yet
  the temple, with its outbuildings, was not entirely complete in the
  time of our Saviour. Herod continued to ornament it and to perfect it
  even until the time of Agrippa (Jos. 'Ant.,' b. xx. chapter viii.
  Section 11). As Herod began to rebuild the temple sixteen years before
  the birth of Jesus, and as what is here mentioned happened in the
  thirtieth year of the age of Jesus, so the time which had been
  occupied in it was "forty-six years." This circumstance is one of the
  many in the New Testament which show the accuracy of the evangelists,
  and which prove that they were well acquainted with what they
  recorded. It demonstrates that their narration is true. Impostors do
  not trouble themselves to be very accurate about names and dates, and
  there is nothing in which they are more liable to make mistakes.