This Bible contradiction is from the Skeptic's Annotated Bible.
Yes, it is good to be childish.
Matthew 18:3 View context
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.
Matthew 19:14 View context
But Jesus said, Suffer little children, and forbid them not, to come unto me: for of such is the kingdom of heaven.
Mark 10:15 View context
Verily I say unto you, Whosoever shall not receive the kingdom of God as a little child, he shall not enter therein.
Luke 18:17 View context
Verily I say unto you, Whosoever shall not receive the kingdom of God as a little child shall in no wise enter therein.
No, it is not good to be childish.
1 Corinthians 13:11 View context
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 14:20 View context
Brethren, be not children in understanding: howbeit in malice be ye children, but in understanding be men.
Ephesians 4:14 View context
That we [henceforth] be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, [and] cunning craftiness, whereby they lie in wait to deceive;