Yes Webmaster.
Technically the new covenant's initiation began in the upper room for the 120 and Peter's sermon that followed was to the rest of the world.
The time between the end of the old and pentecost was the transition period.
The covenant was completed at the Lord's glorification upon rising from the dead and then ready to execute to the world when Pentecost was fully come. All one needed to do, to be filled with the Holy Ghost and have sins removed, was to obey the message that Peter preached as a believer. You had to be a believer. The work had already been accomplished for it. There would be no work that we could possibly do to save ourselves. Jesus did all the work. We obey it.
DMP