Oddly, although posters who have responded range in actual age from 23 to 68 (and I think James Toothpaste may be younger), or a range of 45 years, mental ages only range from 31 to 48, or a range of 17 years. Regardless of one’s actual age the results seem to converge on an average of late 30s/early 40s.
Another median checking in. I’m 46 in the body but my brain is a fresh 36. That sounds about right–haven’t used the damned thing in about 10 years.
Ok, I went through again and checked what seemed to be the most “juvenile” answer each time, and got a mental age of 17. Then I did it a couple more times and checked what seemed like the most “old fart” answers. This time I got ages of 56 and 50. So it seems to be quite hard to get a mental age even as old as I am currently, even trying to do so.
Anyone want to try to score a mental age older than 56?
I’'m 31, the site said 37.
I think I confused it, though, because I’m generally a very boring person, except for my penchant for occasional significant consumption of alcohol.
Also, it asked me like three questions about iPhones and iPads. I don’t use Apple! Leave me alone!
My real age: 29
My mental age: 40
I’m actually kind of flattered that the quiz thinks I’m more mature than I actually am. 
70/21
I should try for old now…
Real: 30
Mental: 42
I’m surprised, I was sure it would come back with a mental age of 12 because I like fast cars and dragons and awesome s&%t like that. Guess I should be yelling at my inner child to get off ma’ damn lawn, ya goldurn little punk!
Actual 59, mental 49.
Ditto. The TV one, for instance - I wouldn’t say there’s never anything good on TV, but none of the shows (or even categories) I like were listed: MASH, Soap, The Muppet Show, Whose Line?, The Wild Wild West, The Man from Uncle, &c…
Real 46, mental 36.
It’s easily torqued to give the mental age desired. And it’s geared toward a U.K. audience, not that there’s anything wrong with that.
Real 61, Mental 37; sounds about right
Real 67, mental 42
Physical age, 50. Mental age, [del]π[/del] 40.
To me, a magnum is a large bottle of alcohol. Or a cheesy '70s-macho-style actor.
I’m 37. Apparently, so is my brain.
No fun. 
Test says I’m 43 mentally…I disagree. I’m 59, but I’m as immature as I was at 35.
Yeah, I didn’t understand any of the choices on that one.
I got stuck at question one. What is a magnum. What is a chocolate flake. And what is an ice lolly?
The thing is, I probably would have gotten the same mental age if I had taken it at 23 as now. I don’t think my preferences on most of the questions have changed that much.
I assumed: ice lolly is a Popsicle. Cone with chocolate flake is ice cream cone and sprinkles. Magnum is a Dove bar product I’ve seem advertised here.
None of the answers for “baseball caps look best…” was “on fire”.