It is legitimate to pray to Mary if you understand what Catholics mean by "praying to" in that context.
See-
Praying to the Saints in Heaven
Are you saying that you never sin and indeed are incapable of sinning?
"Praying to" is plain English, regardless of how Catholics interpret it. Here is a valid definition:
devout petition to God or an object of worship. a spiritual communion with God or an object of worship, as in supplication, thanksgiving, adoration, or confession. the act or practice of praying to God or an object of worship.
Notice it says God or an object of worship. Nowhere in the Bible does it say to pray to anyone but God. Praying to dead people is unScriptural and, to me, very, very strange.
Why are you changing the subject by writing "are you saying that you never sin and indeed are incapable of sinning"? That is a bizarre change of subject. If it's in response to "pray for us sinners now and in the hour of our death", that is part of your "Hail Mary" prayer. Since I am in Christ I am regarded as free from sin. If I sin occasionally, that does not make me "a sinner". That idea is more Catholic error! If I am still regarded as "a sinner" then Christ died for nothing.
Here is some Scripture for you to ponder...
"What shall we say then? Are we to remain in sin so that grace may increase? Absolutely not! How can we
who died to sin still live in it? Or do you not know that as many as were baptized into Christ Jesus were baptized into his death? Therefore we have been buried with him through baptism into death, in order that just as Christ was raised from the dead through the glory of the Father, so we too may live a new life.
For if we have become united with him in the likeness of his death, we will certainly also be united in the likeness of his resurrection.
We know that our old man was crucified with him so that the body of sin would no longer dominate us so that we would no longer be enslaved to sin.
(For someone who has died has been freed from sin.)
Romans 6:1-7 NET