I was raised thinking that the church started at Pentecost in Acts chapter 2. The story I was told was that God finally got fed up with Israel and switched His program to the Gentiles. As if the Gentiles were so wonderful or more receptive or better behaved or something. Translations of the Bible reinforce this story because they pretty much universally use the English word “church” in the New Testament but not in the Old.
The word the translators (and pastors, priests, and rabbis) think is associated with the church is the Greek word we transliterate ekklesia (ἐκκλησία a-klay-see-uh Strong’s number 1577). This word simply means “assembly” or “congregation.” The Hebrew words for assembly or congregation are qahal (6951) and edah. They mean the same thing as ekklesia, and in fact the Greek Septuagint uses ekklesia about 52 times. Sometimes the assembly is formal, such as when kings called Israel together, and sometimes is was an informal family gathering. But ekklesia is not translated “church” in the OT in any of the English translations I consulted.
There’s simply no reason to make an arbitrary distinction for the assembly between the OT and the NT. God’s assembly has been gathering for a long time. The plan of God is continuous, without interruption, and didn’t start in Acts 2. It might’ve gotten a kick in the pants, but the congregation has always been around. The “assembly” that Jesus said He would build (Matthew 16:18) has a foundation that was started in the Garden and goes on into the future as a kingdom that never ends.