"So, now that you're annulled, does this make your children illegitimate?"
Children are gifts from God and thrive best in a sacramental marriage covenant between one man and one woman in a mutual self-gift of compassion, trust, fidelity and love, open to the conception of life. Unfortunately, for many of us, that sacramental covenant was not to be. The Church recognizes that we did have a civil marriage that is now dissolved. The difference is between the sacramental covenant and the legal contract. Annulments only answer the question of sacramentality in a marriage.
Legitimacy of children is a civil, legal status dealing with custodial and, later on, estate purposes. The Church recognizes the authority of the state to govern these legal, civil, temporal aspects.
So yes. My children, all seven of them, are completely legitimate. Thanks for asking.