The point I was making, that I also think God's Word is making, is that Peter in Acts 1 was still running ahead of God the way he always tended to do. He didn't wait for Him to come in the form of the baptism in the Holy Spirit, as Jesus had told him. So their efforts in Acts 1 seemed to come to naught including the selection of Matthias. The weak and futile efforts of the Acts 1 church became powerful and effective in the spirit-filled Acts 2 church.
God called Paul to be an instrument to take the gospel to the gentiles...he did not call him an apostle....
"Apostle" means "one who is sent." As you say, that certainly was Paul. The Word of God calls Paul an apostle in scriptures already referenced and in other verses as well. Paul by the Holy Spirit announced often (he had to, not unlike Jesus) that God had called him to be an apostle. If Paul wasn't an apostle he'd be discredited as a liar by God's Word and the other apostles. But Peter himself acknowledged the truth and wisdom in Paul in 2 Peter 3:15.
And as I say, it does not take away from his teaching to not be called an apostle..
If we are going to imagine the Peter was just too quick and didn't wait for God is not what the scripture states. If we are going to imagine a little (not meant as an insult) I could see Paul calling himself an apostle and Peter getting tired of correcting him just let it ride and left it up to God.
It is written Paul had a thorn of the flesh that he asked God to remove and it was denied. Perhaps this thorn was a little too much pride (he put himself on the same level as the original 12) For he certainly didn't fulfill the necessary terms for being called an apostle, but had to live with the fact that his pride was not taken away as a reminder to be humble before the Lord.
Pride had to be one of his major problems as he was well versed in scripture to the point of feeling he had a right to kill the followers of Jesus teachings.
Those past acts could have been the reason that in scripture, Jesus called him his *instrument* to the gentiles as that would make him not on the same level as the apostles that had followed him since the beginning of his ministry...
I have seen others make the same argument that it was Peter's fault that he was too hasty. That, to me says Gee Whiz God didn't know that, and God should have called him an apostle and he didn't...
Peter was quite clear in what it took to be an apostle (one who was sent) but I am sure, being human, that gave them amongst the followers a little more authority. Remembering all the time that they didn't seek this, but by the nature of their being with the Lord from the beginning this gave them authority..
Perhaps in the beginning, Paul did not like being merely an instrument and in human terms wanted the same authority as the original 12 + and minus one Judas. Add one Matthias...Don't we all to this day think Paul more authoritative than Matthias, yet the lot to be called apostle fell to Matthias for he and the others being considered had all the prerequisites Peter laid out... put side by side, Paul doesn't fall into that category...
But the original 12 with Matthias added was to preach only to the house of Israel and much of what many of them said or taught is not writted down..As all of them were Jews...and well versed in Holy Scripture of the OT.