Cultural differences
In Taiwan and China most people count a child's age starting from 1 not 0. So a newborn child is considered 1 year's old, and someone born on March 1, 1978 will tell you they are 31, at the time of typing this.
More traditionalists go even further and will increment ages on the passing of the new year (based on the Lunar calendar) and not birth date. For a year when Chinese New Year's day falls on Feb 1, a child born Jan 31 would be already considered 2 year's old on Feb 2.
So you see it's just cultural differences. The girls are all 16, the rest of the world is just counting wrong.
Also since when did people using search engines to find stuff become "hackers"? Seriously now, WTF?