Scripture says that the law was introduced because of transgressions, and that Eve, being deceived, was in transgression and that Adam was not deceived and that death entered through him. So, in summary, eve believed wrongly and acted on that, and this was her transgression while Adam believed rightly but acted, fully and knowingly, against that right belief, wrongly. The bible also tells us that the power of death is fear so, I don't think Eve was compelled by fear, but Adam probably did so that death seized its power at first opportunity. Knowing the power of death, then it becomes clearer why the law came in "so that the trespass would increase (Ro 5:20)." and "grace increased all the more." And, "so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord (Rom 5:21)."One important thing I would remind you of is that the law, including the need for a sacrifice for sin, was created for the benefit of humanity, not humanity for the benefit of the law. God, assuming he was the one who needed a price for sin to be paid to Him, could set the price at whatever He chose, He did not need to demand a physical sacrifice. He could have demanded that humans stand on one foot while whistling Dixie and wearing a pink tutu with purple trim. The one harmed gets to decide what will satisfy their honor, not someone else. But if humanity sees sin as a huge problem, then they can easily justify the need for a comparable sacrifice to assuage the dishonor they have committed.
Death did not come in through Eve, so it seems that ignorance was an excuse but, "Now, however, they have no excuse for their sin (John 15:22)." For, "Although God overlooked the ignorance of earlier times, He now commands all people everywhere to repent (Acts 17:30)."
With that said, I think your characterization of 'the need for sacrifice' comes short to characterize it as pivotal on whatever whim God might be inclined toward at any moment. God is the definition of righteous and just and not by any means is He any sort of will imposing 'bully' sort of ruler. "For He has set a day when He will judge the world with justice by the Man He has appointed
(Acts 17:31)."
Scripture doesn't tell us what Adam feared that compelled him to sin against God, so we can only speculate, but whatever it was, Adam was wrong in fearing it rather than fearing his separation from God and the life which comes solely from Him,
So, if sin is to rightly be equated with fearing anything other than separation from the existence of God and all the (correctly understood) characterization and attributes that accompany Him (and I don't believe death is anywhere among those unless anyone can direct me to scripture which might correct me) then evidently Mary at least displayed a possession of worry when she approached Jesus at the wedding in Cana in Galilee. However quickly she might've recovered from it, Jesus intimated His crucifixion, for her specifically, when He said, "Woman, .... My hour has not yet come (John 2:4)."