[Mr Rogers]

Romans 3

“For we have already charged that all, both Jews and Greeks, are under sin, 10 as it is written:

“None is righteous, no, not one;
11 no one understands;
no one seeks for God.
12 All have turned aside; together they have become worthless;
no one does good,
not even one.”

[bdeaner]

You mentioned Romans 3:23 -- "“since all have sinned and fall short of the glory of God” -- presumably as a way to show that Mary was not within sin. There are a number of ways this claim can be shown to be false.

One argument is to look at definition of the word "all" in Strong's. In Romans 3:23 and 5:12, "all have sinned," the Greek word translated into "all" is pantes, which is a derivative of "pas." In Strong's Lexicon, this can mean 1) individually; 1a) each, ever, any, all, the whole, everyone, all things, everythingthing; 2) collectively; 2a) some of all types. It's the latter meaning, "some of all types," that seems to apply in Romans 3:23. We see this same word "pas" in other places where it is used similarly. For example, in John 12:19, "the whole world has gone after him," does not mean the entire world went after Christ. Also see Matt. 3:5-6, "then went all Judea, and were baptized of him in Jordan," which obviously doesn't mean all of Jerusalem was baptized. There are lots of other examples in the Bible but you get the idea. "All" as "pas" is probably better translated as "all sorts of."

Biblical consistency is also at issue here. If "all" really meant every person without exception, that would also include Jesus, who was human -- but that would be too much. Jesus was without sin. And so thus Mary can be without sin.