What is the ruling on adultery before puberty, and is it permissible for a girl who committed adultery when she was young and then repented to wear the niqab?

Parents must raise their children with chastity and modesty. If a girl commits fornication before puberty, there is no sin upon her, as she is not held accountable, according to the hadith: "The pen has been lifted from three: from the sleeper until he awakens, from the child until he reaches puberty, and from the insane until he regains his sanity." When a girl reaches puberty, she is obligated to cover her face from men, adhere to modesty and proper conduct, and avoid mixing with or being in seclusion with non-mahram men.