The apostle named Peter shares how to become a child of God in Acts 2:38, “Peter replied, ‘Each of you must repent of your sins and turn to God, and be baptized in the name of Jesus Christ for the forgiveness of your sins. Then, you will receive the gift of the Holy Spirit.'” Paul, in Romans 10:9-11, says, “If you confess with your mouth that Jesus is Lord and believe in your heart that God raised Him from the dead, you will be saved. For it is by believing in your heart that you are made right with God, and it is by confessing with your mouth that you are saved. As the scriptures tell us, ‘Anyone who trust in Him will never be disgraced.'”
Your salvation in Christ gives you free access to the Almighty God. You are now free to think, move, and act according to His Holy Word. You become a part of God’s family. He adopts you as one of His own; see Romans 8:12-17. Your life is now fully activated to be the hands and feet of Jesus to others who remain in the darkness of their own sins. Unfortunately, 3 enemies come against you: Satan who is the deceiver of this world (2 Corinthians 4:4), this world which is under the authority of Satan right now, and your own flesh.
Satan despises anyone walking 100% with Christ. He doesn’t so why should you? This world doesn’t acknowledge God so unless you separate yourself from its carnal ways, you will follow without realizing the consequences. And your flesh loves itself, so unless you teach it to become obedient to Christ, you won’t follow fully surrendered.
@snfseven says this “A lot of Christians get stuck in the in-between. They say yes to Jesus, but then never grow past the ‘milk’ stage. Hebrews 5:12 says, ‘You have been believers so long now that you ought to be teaching others. Instead, you need someone to teach you again the basic things about God’s Word. You are like babies who need milk and cannot eat solid food.’ This is when confusion comes in. Are they really walking with Christ or just wearing the title? You can’t stay a ‘new believer’ forever. Salvation is the start, but discipleship is the journey.

“The danger of staying in the in-between is you become lukewarm. You have just enough Jesus to ease your conscience, but not enough to transform your life. We’re called to move from milk to meat, to grow up in Christ. We are to bear fruit that shows the world who we belong to. Don’t settle for the in-between. Step into maturity.”
Hebrews 6:1-3 says, “So let us stop going over the basic teachings about Christ again and again. Let us go on instead and become mature in our understanding. Surely we don’t need to start again with the fundamental importance of repenting from evil deeds and placing our faith in God. You don’t need further instruction about baptisms, the laying of hands, the resurrection of the dead, and eternal judgment. And so, God willing, we will move forward to further understanding.” Continue to read what Paul says in verses 4-12.
Walking in a lukewarm fashion puts you in the 10% club. Like snfseven said, are you wearing the Christian title? An indicator that you may be in this club is this, you vacillate between God’s Kingdom and the carnal world. You hang out with Christians in godly settings but that gets tiring and you need to spend time in the world satisfying your own flesh. If God is not transforming your life on a daily basis, where you are surrendering more and more of yourself to Him and enjoying His presence over all things, you will vacillate between two worlds.
Another indicator, do you just give 10% of your time, treasure, talents, and money to God and the Church? You think you don’t have to give anymore. While the giving a tenth of what you own is biblical, it is in the Old Testament only. We are New Testament believers, and Jesus speaks of giving sacrificially. Read the story of the poor widow in Mark 12:41-44 and the farmer in 2 Corinthians 9:6-15 for a couple examples.
God wants you to become fully invested in Him. He gave His all to save you. He needs you to rise up to the calling that He placed within you. Do not let Satan, nor this world, nor your flesh deter you. There is too much at stake, especially in the United States! As the body of Christ, we all need each other to step up and let Jesus lead us as one church, His Church.