God lives fully in Christ. And you are fully grown because you belong to Christ, who is over every power and authority. Christ has also taken away your selfish desires, just as circumcision removes flesh from the body. And when you were baptized, it was the same as being buried with Christ. Then you were raised to life because you had faith in the power of God, who raised Christ from death. You were dead, because you were sinful and were not God's people. But God let Christ make you alive, when he forgave all our sins.
At some point every child is infected with the desire to be a "grown-up." Children want to become adults. That is a natural part of life itself as a child. Children are precious and marvelous, but when someone "never grows up" it is indeed sad to behold.
Wait a minute. Didn't Jesus say that we must all become like little children? Yes He did, but Jesus wants you to be like a child in innocence not in selfish ignorance! The Lord wants you to have the heart of a child, not the actions of a child when you are already grown.
Children are selfish. They want what they want and they want it now! Concern for the needs of others is not part of being childish! If you want to know if you are a grown up Christian then simply look at your selfish desires. If fulfilling your own desires is the ruling principle of your life, then you indeed are still a baby believer.
Here is the most amazing part about growing up as a Christian. Jesus doesn't just change your old man into a new man. That is not the way it happens. The old man dies and you are born again into a new life of following Jesus. So if you wonder why you can't seem to act like a "grown up" as a Christian maybe you aren't dead yet!
"Lord Jesus, I want to grow up and be like you, but I know I can't do that without dying to this world and the things of this world and being made alive by Your great power. And may You be praised forever. Amen."