Christian churches existed at the time of Christ!
MATTHEW 18:20 "For where two or three are gathered together in My name, I am there in the midst of them."
The English word "church" is derived from the Greek word kyriakon, which means something belonging to the Lord.
"`Church' in the New Testament, however, renders Greek ekklesia, which mostly designates a local congregation of Christians and never a building.
Long after the crucifixion the ROMANs hijacked Chrsitianity and renamed it the Holy ROMAN Catholic Church. Not in the Holy lands but entirely in ITALY!
Then they hijacked pagan methods of worship against what the bible teaches!
Thou shall have no other gods! Exodus 20:2-3, Exodus 23:13, Exodus 23:24, Exodus 23:32, Exodus 34:14.
Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth: Thou shalt not bow down thyself to them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me; And showing mercy unto thousands of them that love me, and keep my commandments. (Exodus 20:4-6)
So it matters not whether Mary and the Saints are worshipped as gods, idols, intermediaries or anything else it still goes against God's direct orders!