You mean like a baby? Or 'special' in the way some Olympics are 'special'?
For what it's worth - 0 - when I turned 40 two years ago I felt the classic 'mid-life crises' and promptly went out and got me a 21 year old nude model as my live-in girlfriend. Lasted about four months. LOL
Then, something else 'special' hit me: I grew up. I realized the second half of my life shouldn't (and wasn't going to) be like my first half - as exciting, unpredictable and outright insane as it was - and that I had better get busy setting down some stability for myself. So I started Mister Peabody World and now I DO feel 'all grown up', tho I look (and sometimes act) ten years younger than I am. There's a pride and confidence and, well, mature attitude about me now - except when I'm having fun. That's timeless.
They say a man's (or a woman's?) Greatest Success comes in their 40's and on into their 50's, so there's something to look forward to!
)