The most Blessed Virgin Mary was, from the first moments of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the Human race, preserved immune from all stain of Original Sin. “
How do you get from that to your statement?
If she was sinless, she didn’t need a savior. Only sinners need a savior.
By her calling God her savior, it was her tacit admission of her sinfulness.