I tell people I'm under 90 but also am pleased to be immature young-at-heart, too. I didn't like all the choices available in this quiz. I suspect it was compiled by some smart aleck who has no idea what it's like be over 50 (and still under 90). But the first time I took it, the results said I'm 35. Yeah, sure.
So I took it again, giving slightly different answers for those questions where I'd been ambivalent. 35 again.
Third try, 27 going on 45 with this comment:
The only thing you like better than going to bed very early is proclaiming to the world that you are going to bed very early. Because you are old.
Overall pretty stupid.