If you would rather not broadcast that information to your connections on the social network, you can hide it.
How to hide your birthday notification on Facebook
Here are the few steps you can follow to hide your birthday notification on Facebook. Follow it accordingly.
a. Log in to Facebook and click “Edit Profile” under your name in the left sidebar.
b. Scroll down to the Basic Information section and click “Edit.”
c. Choose “Don’t show my birthday on my timeline” from the drop-down menu under the Birthday heading.
d. Click the audience icon next to your birthday and choose “Only Me.”
e. Press “Save” to complete your changes.