The fact that Mary was human guarantees she was a sinner...
Jesus' flesh/body was not Divine...
Joh 8:23 And he said unto them, Ye are from beneath; I am from above: ye are of this world; I am not of this world.
Jesus' as well as Mary's body/flesh is from beneath...God became manifest in a body that was from beneath...He had to...That was the whole point in being manifest in the flesh...Jesus' body became hungry...It aged...It felt pain...It was tempted...It died...
Jesus’ body and soul were hypostatically united to the Word—the eternal Second Person of the Trinity.
Which is to say that the Word functions as the Act of Existence of the body and soul of Jesus. The body and soul of Jesus have been, since his conception, perfectly sinless and immortal—the opposite of “from below.” When Jesus died on the cross, it was by a free act of his will.
This is orthodox Christological dogma.
Your notion that Jesus’ flesh was “from below” is heretical.