She was a Virgin to fulfill prophecy of Isaiah, that a Virgin would conceive and bring forth a Son....
Jesus got His Humanity from Mary. for the "flesh" physical Body, but by the Holy Spirit conceiving Him, by passed getting the sin nature....
Now you are saying something quite different. I agree Jesus was born of a virgin as a sign.
We are not born with a sinful nature, read Psalms 139:13-16. Here David praises God for making his body.
Psa 139:13 For thou hast possessed my reins: thou hast covered me in my mother's womb. 14 I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well. 15 My substance was not hid from thee, when I was made in secret, and curiosly wrought in the lowest parts of the earth. 16 Thine eyes did see my substance, yet being unperfect; and in thy book all my members were written, which in continuance were fashioned, when as yet there were none of them.
Here David said God fashioned his body. He says he was fearfully and wonderfully made, and God's works are marvelous.
Does God make evil? What would be wonderful or marvelous about being made a sinner?
So, I agree with you, Jesus was not born with a sin nature. But neither were we. We are born flesh, which is weak and easily tempted, but we do not become sinners until we actually commit sin.