What does it mean to become as a little child to enter heaven?

Receive the kingdom like a child. It’s simple faith. Without doubt. You believe what Jesus says, what the Bible says. Like kids believe in Santa Claus. You believe what the Bible says. DOn’t get caught up in the doubt trap. You just believe like a child believes what their parents tell them. Little child… not teenagers and pre-teens. ;-)

Matthew 18:3
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.