Within 40 years of the death of Christ, all but Revelation were written. The church had the Old Testament as well and the NT is sprinkled with references to it.
The Bible was not compiled into a final form until the mid 4th century but there is no reason to think that it was not available to most. Certainly most of the early Christian writers quote rather liberally from passages starting with Clement at the end of the first century.
First of all we have to define what is mean by church and fortunately God’s inspired Bible does such:
Act 2:47 Praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved.
From the onset of the Christian church, Christians dealt with error and contrary to a faulty interpretation of Matthew 16:18, they had error
Gal 3:1 O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you?
Of course the Apostles and earliest Christians were not Catholics
They did not venerate images. In fact until the late 2nd century, Christians would not even make images. They of course did not venerate them when they did but they were certainly opposed to them being hung in a church as when a bishop ripped an image of a man, probably one of the Apostles off the wall in a church in the mid 4th century.
They did not have a Pope. Control of the church was in the hands of the pillars, or the Apostles and James, the first born of Mary after Jesus
“Control of the church passed to the apostles, together with the Lord’s brother James (Eusebius quoting the first Christian historian”
They did not believe that Mary remained a virgin.
To this effect they testify, [saying,] that before Joseph had come together with Mary, while she therefore remained in virginity, "she was found with child of the Holy Ghost;
And as the protoplast himself Adam, had his substance from untilled and as yet virgin soil (“for God had not yet sent rain, and man had not tilled the ground” Genesis 2:5 ), and was formed by the hand of God, that is, by the Word of God, for “all things were made by Him,” John 1:3 and the Lord took dust from the earth and formed man; so did He who is the Word, recapitulating Adam in Himself, rightly receive a birth, enabling Him to gather up Adam [into Himself], from Mary, who was as yet a virgin (Irenaeus).”
They do not believe she was sinless as the Catholic Encyclopedia states:
the older Fathers are very cautious: some of them even seem to have been in error on this matter.Origen, although he ascribed to Mary high spiritual prerogatives, thought that, at the time of Christ’s passion, the sword of disbelief pierced Mary’s soul; that she was struck by the poniard of doubt; and that for her sins also Christ died (Origen, “In Luc. hom. xvii”). In the same manner St. Basil writes in the fourth century: he sees in the sword, of which Simeon speaks, the doubt which pierced Mary’s soul (Epistle 259). St. Chrysostom accuses her of ambition, and of putting herself forward unduly when she sought to speak to Jesus at Capharnaum (Matthew12:46Chrysostom, Hom. xliv; cf. also “In Matt.”, hom. 4
This is also supported by Ambrose of Milan
. For the Lord Jesus alone of those who are born of woman is holy, inasmuch as He experienced not the contact of earthly corruption, by reason of the novelty of His immaculate birth; nay, He repelled it by His heavenly majesty."
John Chrystom talks of Jesus rebuking Mary
. And therefore He answered thus in this place, and again elsewhere, “Who is My mother, and who are My brethren?” (Matthew 12:48), because they did not yet think rightly of Him; and she, because she had born Him, claimed, according to the custom of other mothers, to direct Him in all things, when she ought to have reverenced and worshipped Him. This then was the reason why He answered as He did on that occasion…And since it was probable that if these words had been addressed to her by her Son, she would not readily have chosen even then to be convinced, but would in all cases have claimed the superiority as being His mother, therefore He replied as He did to them who spake to Him; otherwise He could not have led up her thoughts from His present lowliness to His future exaltation, had she expected that she should always be honored by Him as by a son, and not that He should come as her Master….
And so this was a reason why He rebuked her on that occasion, saying, “Woman, what have I to do with thee?” instructing her for the future not to do the like; because, though He was careful to honor His mother, yet He cared much more for the salvation of her soul, and for the doing good to the many, for which He took upon Him the flesh