Kindly reference the following link(s):
Committed Zina, got married but forgot to repent, Will Allah forgive us?
Marriage after committing Zina
Can we marry after committing zina & now she's pregnant? Ruling on the child?
Can I marry the girl I committed Zina / Fornication with?
Stopped zina fornication, repented before marriage but kept communication, Marriage valid?
Couple were in haram relationship (no zina) got married without repenting Nikah valid?