I did not realize you are a translator, or perhaps you, or your denomination/sect, do not accept the KJV, which is what I post from unless otherwise noted.
And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
Mary does not crush Satan's head. The seed of Eve, Christ, crushes his head. Obviously, God used Mary (who is part of the line of Eve) to carry and nurture Jesus. Christ, the seed, crushes Satan.
Rather than create this myself, I am going to post the notes from the NET Bible concerning this passage. All can read and think about it.
Notes for 3:15 [https://bible.org/netbible/ - good resource, continually updated online]
40 tn The Hebrew word translated hostility is derived from the root אֵיב (ev, to be hostile, to be an adversary [or enemy]). The curse announces that there will be continuing hostility between the serpent and the woman. The serpent will now live in a battle zone, as it were. 41 sn The Hebrew word translated offspring is a collective singular. The text anticipates the ongoing struggle between human beings (the womans offspring) and deadly poisonous snakes (the serpents offspring). An ancient Jewish interpretation of the passage states: He made the serpent, cause of the deceit, press the earth with belly and flank, having bitterly driven him out. He aroused a dire enmity between them. The one guards his head to save it, the other his heel, for death is at hand in the proximity of men and malignant poisonous snakes. See Sib. Or. 1:5964. For a similar interpretation see Josephus, Ant. 1.1.4 (1.50-51).
42 tn Heb he will attack [or bruise] you [on] the head. The singular pronoun and verb agree grammatically with the collective singular noun offspring. For other examples of singular verb and pronominal forms being used with the collective singular offspring, see Gen 16:10; 22:17; 24:60. The word head is an adverbial accusative, locating the blow. A crushing blow to the head would be potentially fatal.
43 tn Or but you will ; or as they attack your head, you will attack their heel. The disjunctive clause (conjunction + subject + verb) is understood as contrastive. Both clauses place the subject before the verb, a construction that is sometimes used to indicate synchronic action (see Judg 15:14).
44 sn You will attack her offsprings heel. Though the conflict will actually involve the serpents offspring (snakes) and the womans offspring (human beings), v. 15b for rhetorical effect depicts the conflict as being between the serpent and the womans offspring, as if the serpent will outlive the woman. The statement is personalized for the sake of the addressee (the serpent) and reflects the ancient Semitic concept of corporate solidarity, which emphasizes the close relationship between a progenitor and his offspring. Note Gen 28:14, where the LORD says to Jacob, Your offspring will be like the dust of the earth, and you [second masculine singular] will spread out in all directions. Jacob will spread out in all directions through his offspring, but the text states the matter as if this will happen to him personally.
45 tn Heb you will attack him [on] the heel. The verb (translated attack) is repeated here, a fact that is obscured by some translations (e.g., NIV crush strike). The singular pronoun agrees grammatically with the collective singular noun offspring. For other examples of singular verb and pronominal forms being used with the collective singular offspring, see Gen 16:10; 22:17; 24:60. The word heel is an adverbial accusative, locating the blow. A bite on the heel from a poisonous serpent is potentially fatal.
sn The etiological nature of v. 15 is apparent, though its relevance for modern western man is perhaps lost because we rarely come face to face with poisonous snakes. Ancient Israelites, who often encountered snakes in their daily activities (see, for example, Eccl 10:8; Amos 5:19), would find the statement quite meaningful as an explanation for the hostility between snakes and humans. (In the broader ancient Near Eastern context, compare the Mesopotamian serpent omens. See H. W. F. Saggs, The Greatness That Was Babylon, 309.) This ongoing struggle, when interpreted in light of v. 15, is a tangible reminder of the conflict introduced into the world by the first humans rebellion against God. Many Christian theologians (going back to Irenaeus) understand v. 15 as the so-called protevangelium, supposedly prophesying Christs victory over Satan (see W. Witfall, Genesis 3:15 a Protevangelium? CBQ 36 [1974]: 361-65; and R. A. Martin, The Earliest Messianic Interpretation of Genesis 3:15, JBL 84 [1965]: 425-27). In this allegorical approach, the womans offspring is initially Cain, then the whole human race, and ultimately Jesus Christ, the offspring (Heb seed) of the woman (see Gal 4:4). The offspring of the serpent includes the evil powers and demons of the spirit world, as well as those humans who are in the kingdom of darkness (see John 8:44). According to this view, the passage gives the first hint of the gospel. Satan delivers a crippling blow to the Seed of the woman (Jesus), who in turn delivers a fatal blow to the Serpent (first defeating him through the death and resurrection [1 Cor 15:5557] and then destroying him in the judgment [Rev 12:79; 20:710]). However, the grammatical structure of Gen 3:15b does not suggest this view. The repetition of the verb attack, as well as the word order, suggests mutual hostility is being depicted, not the defeat of the serpent. If the serpents defeat were being portrayed, it is odd that the alleged description of his death comes first in the sentence. If he has already been crushed by the womans Seed, how can he bruise his heel? To sustain the allegorical view, v. 15b must be translated in one of the following ways: he will crush your head, even though you attack his heel (in which case the second clause is concessive) or he will crush your head as you attack his heel (the clauses, both of which place the subject before the verb, may indicate synchronic action).
Biblical Studies Press. (2006). The NET Bible First Edition Notes (Ge 3:15). Biblical Studies Press.