I just noticed that the list of birthdays at the bottom of the page tells everyone exactly how old you are....I think that's just a bit too much information....especially if you're me!! Please take my birthday off the list!!!
You can also hide your information from public view. Go to settings, edit profile, and under your birth date (real or not), make the selection you'd prefer from the drop-down box. Mine is set so that no one can see it.... but you can also choose to show the day without the age, and a couple of other options.