My wife took the test and had me take the test. She scored a 22.
Several of my friends on Facebook have taken it and I've seen scores from 22 to 43.
My youngest daughter took it and she scored a 22 (she's 16).
The test is only six questions. There are no right answers. There were several questions (like the first one) where I wanted to answer, "All of the above", but that wasn't a choice.
I diligently go through each question over and over and just pick the "best" answer even though none of them are necessarily the "right" answer.
Every time I do it, I score a 10. According to this test, I've got the mental age of a 10 year old! What the hell does that mean? My wife says I act like a 12 year old so the damn thing must be off by at least 2 years!
Click the link and hit the green "START" button:
Mental Age Test