I was looking for a Northern Ireland adoption or birth in 1926, we did not know which and birth records in Northern Ireland do not show as less than 100 years ago, but is different for Ireland.
I phoned up GRONI, you could phone the Irish equivalent.
The person I was looking for was adopted officially in 1947 (when they were almost 21). Nothing was known of their adopted family by the person I was doing this for. Also, the adoptive father had already died, so that name is not on the certificate from the adoption register.
You have their exact date of birth, so just explain what you know and see what they can suggest.