He never Baptized anyone & forgiving anybody's sins as a baby , child , teen.
So common sense should tell you those periods were not in play under the NC.
The coming line of demarcation between Old and New was foretold by John the Baptist:
Matthew 3:11
I indeed baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall baptize you with the Holy Ghost, and with fire:
Note that even though Jesus was a grown man the day that John spoke these words nothing as of yet had changed but there was about to be a great spiritual change when
"he that cometh" Makes Himself known.
The baptism of Jesus marked His ordination as Messiah:
Mat 3:16
And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:
With only His temptation by Satan to be completed before the actual beginning of the public New Covenant ministry for the forgiveness of sin began:
Mat 4:17
From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.
I question your assumption that the new covenant only started with Jesus' baptism. Where in the Bible do you find that timing? I don't find it anywhere, including in the verses you quote, and please don't argue from silence.
Please understand that the word "new" (kainos) in the New Testament has a little different meaning from "new" (neos), which means brand-new as in a baby or a young child. "Kainos" means roughly "new and improved." Therefore, the new earth, new heaven, new Jerusalem, new covenant, and other uses of the word refer to both a continuity and a discontinuity. That is, the old covenant continues on in the new covenant but in a different form.
For example, the inner principles of the old covenant remain as moral standards for the international church, but the outward forms as national laws for Israel are no more. As a result, the forms of punishment for murder and adultery are abolished, but anger and lust as their bases are forbidden, as Jesus said in Matthew:
Mat 5:21 “You have heard that it was said to those of old, ‘You shall not murder; and whoever murders will be liable to judgment.’
Mat 5:22 But I say to you that everyone who is angry with his brother will be liable to judgment; whoever insults his brother will be liable to the council; and whoever says, ‘You fool!’ will be liable to the hell of fire.
And in that same sermon, Jesus said that lust is also a sin like adultery, the new-covenant, inner meaning:
Mat 5:27 “You have heard that it was said, ‘You shall not commit adultery.’
Mat 5:28 But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart.
He never Baptized anyone & forgiving anybody's sins as a baby , child , teen.
So common sense should tell you those periods were not in play under the NC.
The coming line of demarcation between Old and New was foretold by John the Baptist:
Matthew 3:11
I indeed baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall baptize you with the Holy Ghost, and with fire:
Note that even though Jesus was a grown man the day that John spoke these words nothing as of yet had changed but there was about to be a great spiritual change when
"he that cometh" Makes Himself known.
The baptism of Jesus marked His ordination as Messiah:
Mat 3:16
And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:
With only His temptation by Satan to be completed before the actual beginning of the public New Covenant ministry for the forgiveness of sin began:
Mat 4:17
From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand.