Childish vs. childlike
There’s a difference between being childish and being childlike.
From what I see in Scripture it would be good if we cast off childishness and keep (or regain) our childlikeness.
When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things.
1 Corinthians 13:11 (KJV)
In contrast:
At the same time came the disciples unto Yahushua, saying, Who is the greatest in the kingdom of heaven? 2 And Yahushua called a little child unto him, and set him in the midst of them, 3 And said, Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven. 4 Whosoever therefore shall humble himself as this little child, the same is greatest in the kingdom of heaven. 5 And whoso shall receive one such little child in my name receiveth me.
Matthew 18:4