Don't be embarrassed to ask questions of your pastor or other people in your church, no matter how simple you may think they are. These people were just like you are when they started their spiritual journey, and they'll want to help you because they love you.
A "worldly Christian" is a person who has put their faith and trust in Jesus Christ, but still clings to his or her old ways of living. Their behavior and their attitudes aren't much different from those of their unbelieving neighbors, and their motives and goals seldom take God into account. When the Apostle Paul addressed the Christians in the city of Corinth, he had to rebuke them for their worldly ways. He wrote, "Since there is jealousy and quarreling among you, are you not worldly? Are you not acting like mere men?" (1 Corinthians 3:3).
Why are some Christians this way? Sometimes it's because they don't really understand what God wants to do in their lives. He wants them to become more like Christ, but they've never understood this. Sometimes, however, it's because they don't want to give up their sinful ways. But no matter what the reason, God's will is for us to submit ourselves completely to Jesus Christ.
Christ gave His whole life for us; should we not give our whole lives to Him in return? Commit your life to Jesus Christ, and then ask Him to help you grow in your faith. God's will for every believer -- including you -- is for us to "grow up in your salvation" (1 Peter 2:2).