Numerical order bares no reference as to worse or better. Nietzsche was refering to the creation account in Genesis however he could have been inferring the first mistake was man, animal, knowledge, science, morality, temptation, creation itself... it's open to interpretation and discussion, as is the nature of philosophy.
My take on it is that it encompasses all, meaning he (God) messed up from the start by creating the earth for the purpose of man yet based on a set of rules that man was never meant to live by, hence the first mistake was creating chaos, the contract was null before we even signed up.
Here's one to justify the hounding of engineers:
"We must be physicists".
He kind of rambles on after that so I chopped it there. I guess it leaves it hanging as whether he was speaking in the imperative or the deductive sense.