When Christians talk about the Gospel, we will almost always talk about Jesus' mother, Mary. Some Christians think of her as mere vessel, while others, including myself, Saint Augustine, and Martin Luther, attribute much more honour unto her. Here I will explain and defend what we believe about Mary.

Mother of God

When we refer to Mary as the "Mother of God" some may think we are implying the Blessed Virgin created God or something similar, but this is far from the truth.
When we say Mary is the Mother of God we are not attributing divinity to her, but to Jesus. We say this because of a short logical process:
A) Jesus is fully human and fully God
B) Mary is the mother of Jesus, the woman who *brought Him into this world*
C) Therefore, Mary is the Mother of God
One objection is that Mary only birthed His humanity, but that separates His two natures. We would say she "bore God on Earth" and served as His human mother; this doesn't deify Mary and doesn't separate Christ's two natures.
We can see her being called the Mother of God in the early church as well:

ca. 215 A.D., Saint Hippolytus of Rome, Bishop of Pontus, disciple of Irenaeus of Lyons, Discourse On the End of the World
1 [The prophets] preached of the advent of God in the flesh to the world, His advent by the spotless and God-bearing Mary.

ca. 250 A.D., Sub Tuum Praesidium
Under your mercy we take refuge, O Mother of God. Do not reject our supplications in necessity, but deliver us from danger, [O you] alone pure and alone blessed.

Immaculate Conception

When we refer to the Immaculate Conception, we are referring to Mary being conceived without sin. Now we do not say this was *necessary*, but we do believe this is the truth.
The New Covenant is the continuation and fulfillment of the Old Covenant, in the Old Covenant the serpent (a fallen angel) whispered a lie into Eve's ear, and she carried that lie to Adam who carried that and through him all Man fell, in the New Covenant an angel gives Mary (the New Eve) grace, and she carries that to Jesus Christ (the New Adam) and through Him all Man can be redeemed. This doctrine gives glory to God and honours Mary, and it truly shows the continuation of Scripture.
Now where in Scripture does it say Mary was Immaculately Conceived? In Luke Mary is greeted by Gabriel who says she is "full of grace", and this is not any small statement:

"The angel Gabriel said, “Hail, full of grace, the Lord is with you” (Luke 1:28 ). The phrase “full of grace” is a translation of the Greek word kecharitomene. It therefore expresses a characteristic quality of Mary.

The grace given to Mary is at once permanent and of a unique kind. Kecharitomene is a perfect passive participle of charitoo, meaning “to fill or endow with grace.” Since this term is in the perfect tense, it indicates that Mary was graced in the past but with continuing effects in the present. So, the grace Mary enjoyed was not a result of the angel’s visit."

The early church affirms this as well:

ca. 155 A.D., Saint Justin the Martyr, Dialogue with Trypho the Jew
100 [Justin:] “[Jesus] became Man by the Virgin so that the course which was taken by disobedience in the beginning through the agency of the serpent, might be also the very course by which it would be put down. For Eve, a virgin and undefiled, conceived the word of the serpent, and bore disobedience and death. But the Virgin Mary received faith and joy when the angel Gabriel announced to her the glad tidings that the Spirit of the Lord would come upon her and the power of the Most High would overshadow her, for which reason the Holy One being born of her is the Son of God. And she replied: ‘Be it done unto me according to thy word’ (Lk. 1:38 )."

ca. 125 A.D., Letter to Diognetus
12:7-9 Let your heart be knowledge, and your life the true teaching that your heart contains. If you bear the tree of this teaching and pluck its fruit, you will always be gathering in the things that are desirable in the sight of God, things that the serpent cannot touch and deceit cannot defile. Then Eve is not seduced, but a Virgin is found trustworthy.

Perpetual Virginity

The Perpetual Virginity of Mary is the doctrine and belief that Mary was a virgin before, during, and after the birth of Jesus Christ, and she remained one her entire life. So, Mary vowed herself in devotion to God to remain a virgin for life, as this was practiced by some women of the day; she was married to Joseph so that he would safeguard and protect her and her devotion to God, he was a caretaker for the Mother of God.
While it is true that the Bible does not explicitly state Mary remained a virgin for life that does not mean that it isn't implied: In Luke 2:41-51 the author describes Mary and Joseph taking Jesus to the Temple at twelve years old; if He had siblings there would have been at least one already born and present.
The verse that mentions His brothers uses the word (adelphoi, meaning brother or brethren) instead of (sungenis, meaning cousin) because Jesus spoke Aramaic or a form of Hebrew, both of which lack a word for cousin.
Furthermore, Jesus uses the word (adelphos, brethren) in non-familial contexts as well, in Matthew 23:8 He calls the crowds and His disciples brethren here; furthering the idea He could have been referring to brethren instead of blood relatives.
The early church taught this as well:

ca. 230 A.D., Origen, disciple of Clement of Alexandria, Commentaries on John
1:6 For if Mary, as those declare who with sound mind extol her, had no other son but Jesus, and yet Jesus says to His mother, “Woman, behold thy son” (John 19:26), and not “Behold you have this son also,” then He virtually said to her, “Lo, this is Jesus, whom thou didst bear.” Is it not the case that every one who is perfect lives himself no longer, but Christ lives in him; and if Christ lives in him, then it is said of him to Mary, “Behold thy son Christ.” What a mind, then, must we have to enable us to interpret in a worthy manner this work, though it be committed to the earthly treasure-house of common speech, of writing which any passer-by can read, and which can be heard when read aloud by any one who lends to it his bodily ears?

ca. 203 A.D., Saint Clement of Alexandria, The Instructor of the Children
1:6:42:1 When the loving and benevolent Father had rained down the Word, that Word then became the spiritual nourishment of those who have good sense. O mystic wonder! The Father of all is indeed one, one also is the universal Word, and the Holy Spirit is one and the same everywhere; and one is the Virgin Mother. I love to call her the Church. This Mother alone was without milk, because she alone did not become a wife. She is at once both Virgin and Mother: as a Virgin, undefiled; as a Mother full of love.

Conclusion

In summary, Mary the Mother of God was conceived without sin and remained a perpetual virgin throughout her life. I, as a Protestant, believe in this due to the support from Scripture, the Early Church, and the Protestant Reformers; and I implore you to look into this further if you have not yet been convinced.
Thank you for reading and God bless.