See 1 Kings 2:2 note, and on the hyperbole contained in the phrase “little child,” compare Genesis 43:8; Exodus 33:11.
How to go out or come in - This expression is proverbial for the active conduct of affairs. (See the marginal reference.)
Related Commentaries of 1 Kings 3:7
1 Kings 3:7
7 And now, O LORD my God, thou hast made thy servant king instead of David my father: and I am but a little child: I know not how to go out or come in.