I am no theological expert, but the question itself goes even further, as the gospels themselves were not written until some 30 years after Christ's Ascension.
I read a book by Bart Ehrman (he is an atheist theologian, by the way), called "Lost Christianities', in which his research indicates that Christianity as we know it today did not really exist until some 400 years after Christ. Up until that point, there were lots of variations in how to worship, so I imagine baptism, Eucharist, etc. were all in flux as well at that point.
That is why they had all those Councils, e.g. Nicaea, etc., as so much had to be thrashed out as there were so many disagreements on what was what.
Doesn't alter the message and the salvation we were given by Christ's life, death and Resurrection, but I think the forms of worship that we now use were subject to change until that point in time (according to Bart, as I stipulate).