Question: Birth Certificate Illigitimate /legitimate

Good day, may I seek for your advice and answer... May LIP ako and due ko na this month (January 2020). Unfortunately hindi sya makakarating dahil naiba ang sched ng route ng byahe nya kaya naextend sila (LIP is a seafarer ?). Plan namin namagpakasal talaga bago lumabas si baby.. Possible ba maging legitimate padin si baby kapag late registration ang birth certificate nya? Ung tipong nailabas na si baby, then mag pa kasal muna kami then kapag married na kmi at my Certificate of Marriage na tsaka nmin iregister si LO ng birth cert. Possible pa din ba na Legitimate si baby? Thank for the answer in advance.