Legitimate/illegitimate child

Hello, good day to all!
I have a 3yr old son who was born out of wedlock. After living in together for quite some time now, my partner (child's father) and i decided to tie the knot next month. However, im already 5 months pregnant now. Here are my questions;
1) will my 2nd child already be considered legitimate by the time he/she is born if we get married now that im 5mos on the way?
2) what are the steps to legitimize my first child?

Thanks in advance!

1. Yes. He will be born within a valid marriage.
2. You and your husband need to execute an affidavit of legitimation. Submit this affidavit, together with your marriage certificate and birth certificate of the first child to the registry where his birth was first recorded. The civil registrar will write on the birth certificate (remarks portion) "legitimated by subsequent marriage" and will indicate the family name that the child will bear and the reference number. This, of course, presupposes that you and the child's father (your future husband) had no legal impediment to marry at the time of the birth of your first child.