I am an average person living near Jerusalem during the earliest periods of the Christian church. While I am of Jewish ancestry, I also recognize Jesus Christ as the Messiah. At what point would I cease to consider myself a Jew and see myself as only Christian?

Theologian here. The answer to question is: Well, that depends. Christian and Jewish explanations of the separation differ.

To the best of our understanding, Jesus, himself, never communicated that participation in the “Way” of his teaching was incompatible in any way with Jewish identity. Rather, he presented an interpretation of Jewish tradition in which his fellowship was an authentic fulfillment of Jewish identity, a (or, rather, “the”) natural progression of Jewish teaching. Comparison between the teachings of Jesus and other Rabbinical leaders in and around his historical context bears this out. Rabbi Hillel, who lived in the time of Herod, was known for saying that the whole of Torah consisted in the command to not do to your neighbor what is hateful to oneself. The positive formulation of this teaching, “Do unto others as you would have done unto you,” is attributed to Jesus. Jesus is also recorded as having participated in traditional Jewish ritual celebrations and communal gatherings.

The same appears to have been true for the early disciples of Christ. They kept Sabbath, attended festivals and synagogues, and generally saw no conflict between being Jewish and being a follower of Jesus.

The tension between these two identities begins to arise in the decades following the crucifixion as two factors emerged for the growing circle of adherents comprising the school/community of Christ. First, Jewish Christians were increasingly excluded from Jewish religious communities. Second, the teachings of Jesus expanded to include a growing number of adherents outside of the Jewish community for whom Jewish traditions and customs (particularly circumcision) were a significant obstacle to participation.

According to the New Testament, the term “Christian” was first applied to the school of adherents following on the teachings of Jesus in Antioch under the leadership of Paul (Saul) in Acts, Chapter 11. If true, this would be a decade or so after the Crucifixion.

The tension between Christian identity and Jewish identity in the Christian record takes shape as struggle between two perspectives, those of the Pauline school and the Jerusalem school. Paul felt that gentile converts to the religion should not also be required to accept the full “yoke” or teachings and religious requirements of Judaism.

By the first century, it’s safe to say that, from the Christian perspective, Christians and Jews were separate groups. Early disagreements had already begun to give way to entrenched animosities. You could put this earlier. Between 66-73 CE, for example, the Roman government exempted Christians from the fiscus judaicus, a tax applied to Jews following the revolt of 66 CE. So, clearly Christians were differentiated from Jews in the eyes of Roman government by that time.

For the Jews, the full separation is generally attached to the period between the destruction of the 2nd Jewish temple in 70 CE and the later Bar Kochba revolt (132-135 CE). In this era, the need to preserve Jewish identity led to the clarification of individuals and schools thought of as “minim,” Jews with incorrect beliefs. Facing a Christian community that was becoming increasingly Gentile in membership, Jewish leaders increasingly perceived Christians not as “minim,” but as Gentiles making a false messianic claim. Around this time the tannaim, Jewish thought leaders, declared Torah with divine names copied by Christians had no sanctity and the writings of early Christians were to be outlawed in Jewish communities. By this time, Jewish Christianity had given way to Gentile Christianity. Leadership of the church had shifted decisively to Rome and Jewish leaders often used the term “notzerim,” or Nazarenes, for members of the Christian community, seeing them as an entirely separate and alien religious group.

So to answer your question: If you’re a Jewish Christian in the years immediately following the death of Christ, you could live your entire life without feeling that Jewish identity and Christian identity were antithetical. You might have some arguments or even violent encounters, but such things were not uncommon in the religious life of the near East between rival schools of thought. A few generations later and things would be different.