Since Mary was sinless, couldn’t God have created her in place of Eve at the beginning of the world? That way there would be no original sin.
Eve was originally sinless herself, but she freely chose to sin. Mary did not. Mary consistently chose to put God first in her life. God designed human beings to be free to choose to be faithful to him or not.
Certainly, he could have created the human race in many other ways, but in his infinite wisdom he chose as he did. In doing so, he made possible the incarnation of his divine Son and the redemption he achieved for us. Alleluia!