You must be in fellowship prior to your Bible study, so that the spiritual information you receive can become a source, of blessing to your soul and produce spiritual growth.
18 Then [epeita] after [meta] three [treis] years [etos] I went up [anerchomai] to [eis] Jerusalem [Hierosoluma] to
see [historeo] Peter, [Petros] and [kai] abode [epimeno] with [pros] him [autos] fifteen [dekapente] days. [hemera]KJV-Interlinear
18 Then three
years later I went up to Jerusalem to become acquainted with Cephas, and stayed
with him fifteen days. NASB
Paul explains with great care, that there was a significant interval of time between his meeting with Christ on that road to Damascus where Paul saw Christ and believed and thus was saved, and the time in which he went to Jerusalem.
Three years had passed.
And the point here is that Paul did not gain his knowledge of the true doctrine of the gospel, from anyone other than through divine revelation from God.
His knowledge and understanding was therefore correct and certain, and thorough.
The after three years, his ministry was to begin.
He then went to Jerusalem, to meet Peter, most probably of the first time. Peter was traditionally viewed as the leader of the apostles and therefore of Christianity.
But remember that just three years prior, Paul, then known as Saul, was the enemy of Christianity. He sought to persecute Christians, even to the point of having them stoned to death. So, in that regard, all Christians would likely be afraid of Saul.
And now that he seems to have changed, that most certainly would have been suspect as a trap. Nevertheless, Peter did meet with Paul and they then became acquainted. The fear of Paul would have been diminished as a result of this meeting.
Paul states clearly that his knowledge came from God during those three years. He therefore does not imply that he went to Peter to consult about what he now knows. After all, who could provide a second opinion to Gods clear instruction? And of course no one could or can do that.
He visited with Peter for fifteen days, and most likely it was Peter who questioned Paul, because of Pauls extraordinary conversion story, and subsequent instruction. Then Paul moved on and went about his business as noted in the next few verses.