What should a person do who committed major sins while ignorant of their ruling in childhood (10-13 years old), then repented, and now at 35 years old is psychologically affected and distracted, even in his prayers, when recalling his old sins and the terrors of the Day of Judgment, especially when he wants to warn his children?

If a person commits major sins before puberty, they are not held accountable for them, unless there are rights of people involved, in which case these rights must be returned. If they commit them after puberty, and then repent and feel remorse, Allah will accept their repentance, for "He is the One who accepts repentance from His servants and pardons evil deeds," and "Indeed, Allah forgives all sins." Therefore, such a person should frequently seek Allah's forgiveness, ask for their repentance to be accepted, and restore any rights. They should also raise their children with noble character, pray for them, and perform many good deeds.