Birthdates were not important to Jews. Yahrzeits were.
Jews used the closest Jewish Holiday as their birthday.

In addition, interestingly, all of the Romanian relatives for which I have
gotten their birth certificate used the date that the birth was reported as
the birth date.

The birth certificate tells the date of birth, they were written in Prose
Longhand but the date of report is at the beginning of the document.
Sometimes the birth certificate will say something like: "the boy was born
the day before yesterday at 10 AM in the home of his parents."

Sometimes the actual date of birth is listed, but the date of the report
seems uniformly to be the date they used.

Surprise to us.

Philip Leonard
Austin