Is sex before the age of menstruation classified as zina?

Question

After my arranged marriage my wife revealed to me that she has been depressed and an anxiety patient all her life. Trying to dig through the reason she revealed to me that she committed sexual acts secretly from a very young age with her cousin who was also of her age. This happened with her consent as she claims she was attracted to her cousin too.

According to her they repeated the sexual acts many a times between the age 6 to 11. This eventually stopped as she somehow didn't feel right about it. She says that it stopped many months before she first experienced her menstruation but she claims that her puberty had started because her breasts had begun to appear in small shape.

The worst of the acts was when her cousin rubbed his private part against hers but they weren't aware of the vaginal opening so complete penetration never happened. It was limited to the clitoral section.

Is this a case of zina because both the people involved were too young. How can she correct the situation for her to experience a closure? Is hadd applicable on her? She has repented all her life after she gained maturity to understand what they had done was a major sin.

Answer 1

I believe this is not recorded in Islam because she was a minor at the time:

Narrated 'Ali: That the Messenger of Allah said: "The pen has been lifted from three; for the sleeping person until he awakens, for the boy until he becomes a young man and for the mentally insane until he regains sanity."
_{Jami` at-Tirmidhi 1423 [grade: hasan]}

(Other sources: Sunan Ibn Majah [grade: hasan] and Sunan an-Nasa'i [grade: hasan].)

See also: At what age does a person become an adult in Islam?

Generally the onset of menses is taken to be the boundary for females (see e.g. Questions on Islam), although Islam Q&A also includes other changes which occur as the result of puberty.