The age_range is not really a valueable info, it only contains the differentiations 13-17, 18-20 or 21+. I guess Spring Social is not supporting this field currently.
The page https://developers.facebook.com/docs/facebook-login/permissions/ is stating
Use any available public profile information before asking for a
permission. For example, there is an age_range field included in the
public profile for anyone who installs your app. This field may be
sufficient for your app instead of requesting user_birthday
permission.
As far as I understood you're using an app already?