It is a hymn about the Savior, Mary’s son, Jesus Christ, who she realized she needed to save her from her own sins.
Mary was a lowly sinner just like you and me. There is nothing in the Word of God that says that she was sinless. She may have been a virgin, but she was not without sin. Otherwise, she would have no need of praising through the Magnificat. She cannot answer our prayers and we are in sin if we dare to pray to someone human entity other than the Mediator, our Intercessor, the Savior, the Lord God Jesus Christ.
INDEED.
One sin, Our Lord Jesus Christ commands us not to commit is to worry and exhibit anxiety. These were all apparent in the gospel account when Mary was looking for Our Lord Jesus Christ for three days. This shows she was not sinless.