I have found this to not be the case. What happens during the first week starting at pip or cut seems to affect future behavior. I had concerns that most of the behaviors including aggression and eating problems were pre-programmed and or genetic, this years experiments so far show that this is not the case. I have one more clutch to go before I have convinced at least myself that "nurture" outweighs genetics.
I'm happy to keep an open mind about this, but then again, I'm not someone who has any difficulty "taming" snakes, so for me, I want snakes to "eat first" and
then "we'll talk..."