Today the priest at the Mass conceded that it might seem to us “easy” that Mary did the things that She did in the Gospels, as She was Immaculate and free from sin. The priest then proceeded, that it can also be easy for us, due to our access to the Sacraments.
But this is what I think. Being free from sin did not make it easier for Mary to do good deeds and voluntarily follow the Lord’s will, because there was, strictly speaking, less motivation for Mary to do that. We all are often motivated to serve God and do good deeds because of our sinfulness - because we need to get cleansed from our sins.
Our Blessed Mother did not have this motivation. So, although it might have been easy for Her to perform what She was obliged to do (holding the Sabbath, being faithful to the husband, etc.), everything “overdue” that She did (giving birth and raising Jesus, etc.) was much harder for Her, as She did it all by Her pure good will, without any necessity. This is why the temptation of the devil to say “no” to anything She did might have been much stronger that with us. Possibly, even immeasurably stronger.
So, in this way, Her merits are immeasurable, incomparable with the merits of anyone else in the Church, except for Her Son.