That's debatable, also your daughter is too young to think for herself. Most people can't remember anything until they reach like 5 or 6 years old.
Your question/point about the "sin nature" reminds me of the following which you may have already heard in some form or fashion:
One day, a scorpion asked a frog for a ride across the pond on his back.
The frog replied, "I'll give you a ride across the pond on my back under one condition...that you promise not to sting me."
The scorpion replied, "I promise not to sting you."
The scorpion then proceeded to get upon the frog's back, and the frog carried him across the pond. As soon as they reached the other side of the pond, the scorpion stung the frog.
As the frog lay there dying, he asked the scorpion, "Why did you sting me when you promised me that you wouldn't?"
The scorpion replied, "I'm a scorpion...it's my nature to sting."
Unregenerate man definitely has a fallen nature.
The Apostle Paul put it this way while writing to those who had become saints at Ephesus:
Ephesians chapter 2
[
1] And you hath he quickened, who were dead in trespasses and sins;
[
2] Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience:
[
3] Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others.
Prior to their conversions, these Ephesians all walked in time past according to the course of this world, according to the prince of the power of the air or Satan, the spirit that now works in the children of disobedience, and they were all BY NATURE the children of wrath.
This fallen nature is precisely why we all need to be "born again", spiritually speaking.
Anyhow, people do horrible things because of their nature.
You'll know a tree by its fruit, and not by what it professes to be.