Only sinners need saviors. If Mary considered that God was her savior, it demonstrates that she recognized that she was a sinner in need of a savior.
Luke 1: 46 & 47 And Mary said: My soul doth magnify the Lord. And my spirit hath rejoiced in God my Saviour.
Claiming Mary was without sin denies the clear teaching of the Bible that ALL have sinned and that there is none righteous, but that all need a savior.
Romans 3:22-24 This righteousness from God comes through faith in Jesus Christ to all who believe. There is no difference, for all have sinned and fall short of the glory of God, and are justified freely by his grace through the redemption that came by Christ Jesus.
Romans 5:12 Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all men, because all sinned—
This puts you at odds with 90% of Christendom.