Turn to ACTS chapter 2 and look with me at all the reasons why the Church started during the worst possible time.
Verse 1: Just fifty days had passed since the crucifixion of Jesus. Jerusalem was still incensed with the episode and were in no way sympathetic to Jesus or His disciples.
Verse 5: The crowd was made up of devout Jews who were of no mind or intention to change their religious views.
Verse 13: Many thought that Peter and the disciples were drunk. They openly mocked them. This was an hostile crowd. You know what an hostile crowd is like right? Angry, shouting, pushing, skirmishing.
Verse 17: Peter starts to proselitize. He starts preaching the prophets. How often have you spoken the truth to someone and they accuse you of "preaching"? Well, what else are we supposed to do? It is by the foolishness of preaching that the gospel is proclaimed.
Furthermore, it is by the foolishness of preaching in the face of conditions that most other people (dare say, Christians) would say, "This just isn't the right opportunity to share the gospel." More often, you probably hear it said this way during a nice quiet prayer meeting, "I'm going to see such and such a person. They are very negative to the things of the Lord. But I just feel so burdened to witness to them. Please pray that God will give me the right opportunity."
Now suppose that Peter and the disciples felt that way on the day of Pentecost. If anyone had the right to assess the situation as a bad opportunity (read no opportunity at all) it would have been them. They could have just retreated back to the upper room and prayed about it. But they realized something that most of us are not willing to believe.
We don't wait for opportunities. We are the opportunity.