Evidently, as much as Catholics would like to honor Mary, the fact remains that she required, as you noted, a Savior...and thus was simply a human sinner like the rest of us. This unavoidable conclusion makes veneration a tragic, overworked error on Rome's part. Sorry.
It is not at all unheard-of for a person to receive the Holy Spirit and be saved in their mother's womb (John the Baptist did; Isaiah and Jeremiah too, since they were made prophets in their mothers' wombs, and the Holy Spirit spoke through the prophets.) In this manner, they foreshadowed or paralleled her. Did they or did they not receive the Holy Spirit as embryos and fetuses?
Like them, Mary was saved in the womb. And, as is fitting, to an even more wonderful degree: she was free from sin from her very conception, from when she was a zygote.
Prenatal reception of God's grace is a pro-life Biblical theme, my friend!
We say this because of the wonderful and unparalleled title the very angel of God gave her: Kecharitomene. The angel didn't call her "full of sin". He called her "full of grace". So Biblically, he did not address her as a sinner, but quite the contrary as one full of grace. And this was before she even became pregnant with God's Baby.
All glory to the Lord Jesus Christ, her Savior and ours.