Go to My Settings at the top, then Edit Your Details on the sidebar. Under the box that says Date of Birth, there's a thing that says Privacy: and a dropdown list. Select "Display Only Age" (or whatever you prefer) from the list. Then scroll to the bottom and hit Save Changes. Should display your age on both the side here and on your profile.
Go to My Settings, and then go to Edit Your Details under the sidebar Your Control Panel. There'll be a section called "Registration Required Information - All fields are required." Under there is a section "Date of Birth", and there's a bit there where you can fiddle around with the privacy settings. Once you're done, scroll all the way to the bottom and click Save Changes. Hopefully this helped =] If you have any questions, please feel free to ask them. EDIT: I was beaten! Aw, heh
