You forget that Jesus told the apostles NOT to go to the Gentiles, but to the lost sheep of Israel. (Matt 10:6-8)
Matthew 10:5-6: “These twelve Jesus sent forth, and commanded them, saying: "Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not: but go rather to the lost sheep of the house of Israel.” Jesus Himself said he was sent only for the lost sheep of Israel. (Matt 15:24)
It took a while for the early church to recognize that salvation was available to the Gentiles. The Jewish Christians who fled the persecution in Jerusalem went into the Gentile regions of Phoenicia, Cyprus and Antioch, but they were “spreading the word only among Jews”(Acts 11:19)
Read the story of Cornelius. Peter did not want to go to this man's house because he was still keeping the law refusing to touch anything unclean, but God had to open his eyes about the Gentiles.
Yes, eventually the Gospel was preached to all the world.
A little study is a wonderful thing. :)