I don't even want to know how or why you found that website...
Old Fart Pride.
I discovered that, while the age recognition algorithm can sometimes be uncanny in its accuracy (I uploaded 4 different photos of my adult son at different ages--and it nailed them), their algorith that determines what is a face seems to have a lot of difficulty if the background is busy and in-focus.
It uses machine learning algorithms on vast quantities of known data to predict the age of a face (new data). But a separate algorithm bears the burden of figuring out what in a photo is a face.
The website was intended as a test for the age determination algorithm. Invitations were sent out to several dozen people. Oops! It went viral, and showed up in multiple news streams.
Before emailing the link to friends or relatives, you might want to do a trial of some photos of them, to determine if they will be pleased or pissed off at you.
Bob