My point was answering against the idea that just because someone is born without the original sin, they would not need the sacraments, or that they were unable to sin at all.
Our Lady still needed the sacraments because She was still subject to the Old Law (i.e. purification) and also the Church, post Pentecost. The protestants reduce everything to grace/sin, which is an error. Our Lady needed the sacraments because of Church AUTHORITY (i.e. baptism is required for salvation and so is the Eucharist, for adults). This is the part that protestants want to ignore - that Christ created the Church with RULES and even Our Lady needed a Savior (so She says in the Magnificat), even if She didn't need a Redeemer (because She didn't have original sin).
Our Mother was capable of sin if I understand correctly the doctrine, she simply didn't sin at all during her life through her own choices, which can be considered to be extraordinary because Adam and Eve were not capable of doing so.
This is not exactly true. We have to understand the nature of Adam/Eve, pre-sin. They were not tempted to lust, or envy, or hate, or any sins related to our fallen nature. They were only tempted by PRIDE, (similar to the angels) because Adam/Eve's nature was in a perfect state. Lust, envy, hate, etc are sins whereby the emotions/will rebel against the intellect. But this was not possible for Adam/Eve because their intellect/reason was IN CONTROL of all their human faculties. The only way for them to sin was through their intellect/reason, which we call pride.
In the same way, Our Lady could not sin by way of her lower nature, because Her lower nature was not corrupted. Therefore satan wouldn't tempt Her in this area; it was off-limits to hell to tempt Our Lady, which is why She is so unique and holy. And because the only way She could've sinned was through pride (i.e. intellect/reason), and She didn't, this is why the devils hate Her so much, because She is literally, the most-humble person who has ever lived (and the most humble of all creatures COMBINED) because not once did She ever sin through pride, but her humility was constant, perfect and pleasing to God in every way.
So, yes, in theory Our Lady could've sinned ONLY through pride (but She did not). But it's incorrect to say that She was tempted to impurity or anger, etc. Neither was Our Lord tempted to any of these sins, because His passions were ordered and controlled (just like Our Lady's) by reason, as God originally designed Adam/Eve.