Maybe we should create a follow-up thread to discuss Revelation haha. Given how complicated that book is, I suspect that thread could go on for years.
I would say that the three strongest reasons that support interpreting the woman of Rev. 12 to be Mary are:
(1) she gives birth to the ruler of all nations, whom the dragon hopes to devour (v. 5);
(2) the absolute animosity that the dragon has for the woman (v. 13-17) hearkens back to Gen. 3:15, which is a passage that theologians have called the "protoevangelium" or "first Gospel," because God foretells that the serpent's head will one day be crushed. Catholics believe, for many different scriptural reasons, that Mary is the new Eve promised by God in the protoevangelium. And the dragon's complete hatred for the woman in Rev. 12 seems only to confirm that she is the woman of whom God foretold in Gen. 3:15; and
(3) the ark of the covenant is seen in Rev. 11:19, only one verse before the woman is seen.
This gives me a chance to delve in fully as to why Scripture reveals unequivocally that Mary is the ark of the new covenant. I think this is really cool and mind-blowing:
Consider Heb. 9:4, Lk. 1:41-44, 56; 2 Sam. 6:9-16, and Ex. 40:34-35, and let me explain why I had pointed to these earlier. Hebrews 9 tells us what was contained within the ark of the covenant--namely, (1) the manna that sustained the Jews in the dessert; (2) the staff of High Priest Aaron; and (3) the 10 Commandments. All of these items prefigure Jesus who of course is (1) the Bread of Life (Jn. 6:35); (2) our High Priest (Heb. 3:11); and (3) the Word and Law (Jn. 1:1). The ark of the covenant contained these three items the same way that Mary contained Jesus in her womb.
Next, compare Lk. 1:41-44, 56 and 2 Sam. 6:9-16. This passage in 2 Sam. 6 details the ark of the covenant's entry into Jerusalem. In this episode, we see (1) that David leaps and dances in the presence of the ark; (2) David asks, "How can the ark of the Lord comes to me?"; and (3) the ark stays in the home Obededom for three months. Likewise, in Lk. 1:41-44, 56 we see (1) John the Baptist leaps in Elizabeth's womb when Mary approaches; (2) Elizabeth asks, "How does this happen to me, that the mother of my Lord should come to me?; and (3) Mary stays in the home of Elizabeth for three months.
Additionally, this same episode in Luke tells us that Elizabeth, filled with the Holy Spirit, "cried out in a loud voice" (Gk. "anephonesen"). This word is rarely ever used in the Bible--in fact, it's only used five other times (1 Chron. 15:27, 16:4, 5, 42, 2 Chron. 15:13), and each of these five times are in the context of Jewish liturgical celebrations done in the presence of the ark.
Next, we should compare Lk. 1:35 and Ex. 40:34-35. In this passage in Luke, Mary is told, "The holy Spirit will come upon you, and the power of the Most High will overshadow you." In Exodus, the passage, describing the Tent of Meeting where the ark of the covenant was kept during the exodus, explains that "the cloud of the Lord overshadowed the Tent of Meeting and the glory of God filled the tabernacle. Moses could not enter the Tent of Meeting, because the Cloud had settled down upon it, and the glory of the Lord filled the tabernacle." It's hard to miss the parallel language here. The same Greek word "episkiasei" (Eng. "overshadow") is used in Luke, just as it is in the Greek Septuagint.
Once we realize all of the parallels between Mary and the ark of the covenant, it becomes clear that the New Testament present Mary as the ark of the new covenant. And once we realize this, it does not surprise us to see the ark of covenant in Rev. 11:19, one verse before we see the woman in Rev. 12:1. The fact that the two are seen together confirms that the woman must be Mary.