Since when were the disciples not 'worldly'? Everyone wants to make out like the disciples were these super pious, holy people but they werent. They were common men, mostly manual laborers, who constantly bickered among themselves, questioned Christ, doubted Him and were generally worldly and contentious. In fact Christ most often chose worldly, poor, common men to be his disciples over wealthier men. He chose men he knew would be loyal and hard working and would be able to speak to other commoners on their level. You understand that Jeus ministry wasnt just about walking all over the country side preaching and teaching and starting a church right? It was about gathering men and training them in Gods word and teaching them to train others. Christs ministry was training them as well as spreading the word. They were also his closest friends. So when it was time for him to die and it was time for Jesus last meal who better to spend it with and provide a final lesson. He knew the agony he was about to suffer and he knew the pain and fear his friends and followers were about to suffer. He wanted to spend his last big meal with friends and he had a final and very important lesson to teach them as well. This was the moment he passed the Church into the hands of his disciples. Maybe Jesus already even knew that many of the men in that room would end up martyred for the Church. Im not sure who you think Jesus should have eaten with but i cant imagine any better representatives of 'worldly' people than fishermen and laborers and tax collectors and whomever else who had followed him for three years and knew him and his purpose better than anyone else
The reason why Jesus had the Eucharist with his disciples was because they are the ones who were his followers. Another reason is because the Eucharist is given among the followers and believers of Jesus.
Just remember that Jesus introduced the Eucharist at the Last Supper--very shortly before he was crucified. And he was teaching his disciples what to say and do when they went out into the world to witness to the people of the world. And that is exactly what they did. You can think of it as though He was planting a crop that his disciples would harvest and then distribute.
During this last meal with His apostles, Jesus took two symbols associated with Passover and imbued them with new meaning as a way to remember His sacrifice, which saves us from spiritual death .Also during the Last Supper, Jesus taught the principle of servanthood as He washed His disciples' feet, (Luke 22:26-27). It was both a Passover meal and the last meal Jesus had with His apostles before His arrest and subsequent crucifixion. One of the important moments of the Last Supper is Jesus' command to remember what He was about to do on behalf of all mankind: shed His blood on the cross thereby paying the debt of our sins (Luke 22:19) . In addition to predicting His suffering and death for the kingdom of God (Luke 22:15-16), Jesus also foretold Peter's denial of Him (Luke 22:34) and Judas Iscariot's betrayal (Matthew 26:21-24).http://www.gotquestions.org/Last-Supper.html Jesus was preparing His "worldly" people to go out into the world.