90. What is the beginning and ending of the state of Jesus as Son?

The Son of God had a beginning at the time of conception . The state of the sonship will end when the reason for the sonship (redemption) is complete.

1 Corinthians 15:22
22 For as in Adam all die, even so in Christ shall all be made alive.
23 But every man in his own order: Christ the firstfruits ; afterward they that are Christ’s at his coming.
24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
25 For he must reign, till he hath put all enemies under his feet.
26 The last enemy that shall be destroyed is death.
27 For he hath put all things under his feet. But when he saith all things are put under him, it is manifest that he is expected, which did put all things under him.
28 And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.