John MacArthur preached on the reconciliation (2 Cor. 5:17-21) and included the answer to this question.
He said, "I must fulfill all righteousness. He said that to John the Baptist, remember, "I must fulfill all righteousness." (Matthew 3:15). When the writer of Hebrews says He was tempted at all points like we are yet was without sin, "all points" are chronological. He was tempted the way a child was tempted. He was tempted the way a young person was tempted. He was tempted the way a young adult was tempted. He was tempted at ALL points in the chronology of human life. He lived a complete life into adulthood, tempted every way possible that a human being could be tempted...and yet without sin. Why does there have to be this complete, sinless life? Answer: so that sinless life can be credited to your account. Understand it this way- on the cross, God treats Jesus as if he lived your life so He can treat you as if you lived His.Jesus is estimated to have lived 33 years. The Compass Point system of headings has 32 "points of the compass". Jesus was tempted "at all points" from birth to death in adulthood and all points in between." It's not exact, but I like the visual.
This one's prettier
How I long for my tongue not to be limited to mere constraining words, so I can express the beauty of Jesus in more complete terms. When we are glorified, I pray that our fullness in body and mind will allow a more expansive expression of devotion to the One who is beyond superlatives. For now, here is a psalm of praise-
My heart overflows with a pleasing theme;
I address my verses to the king;
my tongue is like the pen of a ready scribe.
You are the most handsome of the sons of men;
grace is poured upon your lips;
therefore God has blessed you forever.
Psalm 45:1-2
