According to this study, it's 35.

http://www.bbc.com/capital/story/20170913-is-this-the-age-we-lose-our-youth

What’s the perfect age? For some it’s the carefree teenage years or time at university. But 35 may in fact be the pivotal turning point, both personally and professionally.
Not only is 35 the age when we’re perceived to no longer be "young", according to a study from the University of Kent, but also when men reach "peak loneliness" and women hit "peak boring." And if that wasn’t bad enough, 35 is also the age at which we start hating our jobs, according to a survey of more than 2,000 UK employees by human resources company Robert Half.

Research suggests it’s during your mid-thirties that family pressure and increased financial responsibility conflate causing problems both at work and home.

Job security also becomes more of an issue. In the first quarter of 2017, UK workers aged 35-49 were twice as likely to be made redundant as those aged 25-34, according to data from the Office for National Statistics.

Moreover, this group were less content at work than their younger peers, the Robert Half UK survey found. It revealed that one in six British workers over the age of 35 were unhappy in their job – more than double the figure for those under 35.

Women who want to have children still face anxiety over their fertility post-35 although recent research suggests fertility doesn’t drop as sharply as once imagined. In the US, an increasing number of women are now postponing their first pregnancy well into their 30s to continue education and forge careers. The latest statistics from the US Centers for Disease Control and Prevention suggest that, for the first time in recorded history, women in their early 30s are now having more children than those in their 20s.

“Previously people made definitive lifelong decisions in their early 20s, but today’s millennials are continuing to defer decisions,” says Jeste. “They’re getting married later in life, they’re having children later in life, and a lot of these stresses that once happened earlier in life are now happening in the 30s.”

The good news? “The rest of your life is going to be happier,” says Jeste.
Of course, ageing isn’t a glamorous affair but your mental health may improve as the decades pass “we know ourselves better, we make informed decisions and we tend to be less selfish,” Jeste says. “That’s the wisdom that comes with experience, which only comes from ageing.”

Meh, I'm 33. I'm still partying pretty hard.

Fuck. I'm 28, all my friends are married and hate their life and college debt, and I'm looking for a future ex gf to go to Nashville with this weekend.


Fuck being old

It's always relative.

I remember being four years old and thinking that nine was old.

I developed presbyopia at age 42 and have worn bifocals since then.

The AARP started sending me solicitations about six months before my 50th birthday, so at least they regard 50 as old.

In February I will have my 60th birthday.  A lot of people regard that as the threshold of old.

My mom is 83 and still thinks of me as a kid.

As long as I can get it up without drugs I am not old !

You are old when there is no one younger than you playing pro sports.

When the only pussy you can get is at The Villages.

Study is pretty accurate in its summary and how genders respond.  On another note your only as old as you act but it's more talking perceptions

You're as old as you feel.

Most of the guys I work with who are half my age act like little old men.

35 was when my body started falling apart, and exercise no longer made me stronger. The beginning of a long death.

Adult age category progression:  young, younger, middle-aged, older, old, elderly, ancient.  Where those categories divide is based on the age of the subject and the perspective of the observer.

Duh. The answer is 87.

I've been considered old since my mid 20s.  

I love the old man lifestyle.  

Leave me the fuck alone.

I'm 55 and that is old.

When did Gary Player retire? 

I call my husband a pawpaw all the time.  He says things like *shortpants* and sings along to OLD country gospel music.  He's an old soul but looks really young which is hilarious to me.

I this where I get to say 87 ?

Pretty well hit the wall at 67.

Sixty Five

I'm 48. I identify with all that stuff, and have for a while. :/

I'm 35. Still party hard. Workout almost everyday. Get carded everywhere I go.

I'm gonna go with 70's is oldish and 80's is old.

That one REALLY pissed me off, kind of like when they stopped carding me for alcohol purchases.

Or when you are older than the President of the United States, as I was with Obummer.

As George Burns one said.  Old is fifteen years older that I am.  I'm 65 and I don't feel old.

I said sports.

LOL, it pisses you off when you're young and depresses you when they stop.

That is a cool reply.

5 years older than I am..... In theory, I'll never be old...

You're middle aged when you start having back pain and you're old when you have your first heart attack

Meh, I dunno

I remember my Mom turning 45, and i thought she looked like a Grandma.

I'm 48 now, and I'll fight anyone here, even though I will probably get my ass kicked..LOL

When you start considering yourself 'old'

10 years older than the person making the determination.

50 is the new 30

I'm 5x and still moving!

My Dad was pretty much a total badass until he hit his late 60's. He's starting to slow down now.

70 starts it

Motherfucker...

40s are when you start showing classical signs of "old age" and things just start to hurt.

I'm 66, you will have to ask someone older than me,so.....................?  

10 years older than me.

I call people old past age 32
ETA this thread smells like mothballs and old people

I'm 34 and I'm honestly in the best shape of my life. My 22yo girlfriend calls me old though.

When the guys catching touchdowns in the NFL are younger than you. So at 30, I consider myself old.

j/k  

Because when you were 22 she was 10

I'm 46 and don't feel that old, though the orthopedist whom injects cortisone into my right knee says that it has a 25 year head-start in the rest of me.

... when you give up on feeling/acting young

Until a man is twenty-five, he still thinks, every so often, that under the right circumstances he could be the baddest motherfucker in the world. If I moved to a martial-arts monastery in China and studied real hard for ten years. If my family was wiped out by Colombian drug dealers and I swore myself to revenge. If I got a fatal disease, had one year to live, and devoted it to wiping out street crime. If I just dropped out and devoted my life to being bad.

- Neal Stephenson, Snow Crash

How about a stroke and a brain tumor?

I have been old most of my life and it worked well until I got old...At almost 58 I wish I could see 35 again.

shit I felt damn good at 35.   liked my job,  liked my life  was dating a asian woman 10 years younger than me


at about 38 is when i noticed changes in myself.

hair in places you usually think of as old,   hair started to really  fall out at a faster pave than it was.    ulcers put me in the hospital.   started pulling my back muscle more often

now past 40 I mentally think of myself the same as when I was 18 but   I can see the difference in my health big time . of course the crohns has a lot to do with that