Please consider the following from two Evangelical theologians on the four principal views on the progression of Early Christianity.
1. "...Adolf Von Harnack:...Hellenism influenced the post-New Testament Church to the point of eradicating the original sense of the Gospel message."
2. "...(Cardinal Newman):...the Christianity that originated with Jesus and his apostles was merely the starting point of a series of theological developments that continued to evolve over the centuries."
3. The Bauer-Ehrman thesis that there were many varieties of Christianities that were eventually suppressed by the proto-orthodox led by the Church of Rome (my paraphrase of Chapter 1).
4. "...(Father) John Behr, dean and professor of Patristics at St. Vladimir's (Orthodox) theological seminary: ...the theology that the emanated from the new testament, continued through the church fathers, was guarded by the apologists, and solidified in the ecumenical church councils represents a continuous uninterrupted stream. The theology espoused by the orthodox clarified, elucidated, and expanded the theology of the new testament without deviating from it, and the creeds accurently represent the essence of the apostolic faith."
The Heresy of Orthodoxy: How Contemporary Culture's Fascination with Diversity Has Reshaped Our Understanding of Early Christianity, by Andreas Kostenberger and Michael Kruger, Crossway, 2010, page 53.
The Evangelical authors agree with Father Behr, making it most unlikely that your claim is correct; preserving the ancient faith is not merely fundamentalist malarkey but is of critical importance. I am not saying that you are not free to become anything you want; what I am pointing out is that there are only four ways at looking at Early Christianity, which is indeed the truest Christianity. It is up to you to choose.