What age? The Christian age? the Church age? the New Covenant Age?
Whenever it began, we can be certain it hadn't begun, nor do the apostles have any idea it would begin, when the apostles asked Jesus "when will the end of the age be"? Manking it impssible that the apostles were asking, and Jesus was answering "when" would be the end of the Christian age.
The apostles had more knowledge about some of these things than you are giving them credit for, thus you are disregarding what Jesus had already taught them in the past, such as what is recorded in Matthew 13 per the following.
Matthew 13:36 Then Jesus sent the multitude away, and went into the house: and his disciples came unto him, saying, Declare unto us the parable of the tares of the field.
37 He answered and said unto them, He that soweth the good seed is the Son of man;
38 The field is the world; the good seed are the children of the kingdom; but the tares are the children of the wicked one;
39 The enemy that sowed them is the devil; the harvest is the end of the world; and the reapers are the angels.
40 As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world.
41 The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity;
42 And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth.
43 Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear.
Doesn't this involve the end of the world? Is there any reason to think that the end of the world meant here is not the same end of the world meant in the Discourse? The Greek word for 'end' in verse 39 is sunteleia. It is used in only 6 passages total in the NT, that being all of the following.
Matthew 24:3 And as he sat upon the mount of Olives, the disciples came unto him privately, saying, Tell us, when shall these things be? and what shall be the sign of thy coming, and of the end(sunteleia) of the world(aion)?
Matthew 28:20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end(sunteleia) of the world(aion). Amen.
Matthew 13:39 The enemy that sowed them is the devil; the harvest is the end(sunteleia) of the world(aion); and the reapers are the angels.
Matthew 13:40 As therefore the tares are gathered and burned in the fire; so shall it be in the end(sunteleia) of this world(aion).
Matthew 13:49 So shall it be at the end(sunteleia) of the world(aion): the angels shall come forth, and sever the wicked from among the just,
Hebrews 9:26 For then must he often have suffered since the foundation of the world: but now once in the end(sunteleia) of the world(aion) hath he appeared to put away sin by the sacrifice of himself.
If you try and use Hebrews 9:26 to make your case then you need to show how the verses in Matthew 13 above are involving what Hebrews 9:26 is involving. They both involve the end of the world, yet they are not involving the same events, obviously.