Meg Jay，a clinical psychologist
Ted，February，2013
When I was in my 20s，I saw my very first psychotherapy client.I was a Ph.D.student in clinical psychology at Berkeley.She was a 26-year-old woman named Alex.
Now Alex walked into her first session wearing jeans and a big slouchy top，and she dropped onto the couch in my office and kicked off her flats and told me she was there to talk about guy problems.Now when I heard this，I was so relieved.My classmate got an arsonist for her first client.（Laughter）And I got a twenty something who wanted to talk about boys.This I thought I could handle.
But I didn’t handle it.With the funny stories that Alex would bring to session，it was easy for me just to nod my head while we kicked the can down the road.
“Thirty‘s the new 20，”Alex would say，and as far as I could tell，she was right.Work happened later，marriage happened later，kids happened later，even death happened later.Twentysomethings like Alex and I had nothing but time.
But before long，my supervisor pushed me to push Alex about her love life.I pushed back.I said，“Sure，she’s dating down，she‘s sleeping with a knucklehead，but it’s not like she‘s going to marry the guy.”And then my supervisor said，“Not yet，but she might marry the next one.Besides，the best time to work on Alex’s marriage is before she has one.”
That‘s what psychologists call an“Aha！”moment.That was the moment I realized，30is not the new 20.Yes，people settle down later than they used to，but that didn’t make Alex‘s 20s a developmental downtime.
That made Alex’s 20s a developmental sweet spot，and we were sitting there blowing it.That was when I realized that this sort of benign neglect was a real problem，and it had real consequences，not just for Alex and her love life but for the careers and the families and the futures of Twentysomethings everywhere.
There are 50million Twentysomethings in the United States right now.We‘re talking about 15percent of the population，or 100percent if you consider that no one’s getting through adulthood without going through their 20s first.
Raise your hand if you‘re in your 20s.I really want to see some Twentysomethings here.Oh，yay！Y’all‘s awesome.If you work with Twentysomethings，you love a twentysomething，you’re losing sleep over twentysomethings，I want to see—Okay.Awesome，Twentysomethings really matter.
So I specialize in Twentysomethings because I believe that every single one of those 50million Twentysomethings deserves to know what psychologists，sociologists，neurologists and fertility specialists already know：that claiming your 20s is one of the simplest，yet most transformative，things you can do for work，for love，for your happiness，maybe even for the world.
This is not my opinion.These are the facts.We know that 80percent of life‘s most defining moments take place by age 35.That means that eight out of 10of the decisions and experiences and“Aha！”moments that make your life what it is will have happened by your mid-30s.
People who are over 40don’t panic.This crowd is going to be fine，I think.We know that the first 10years of a career has an exponential impact on how much money you‘re going to earn.We know that more than half of Americans are married or are living with or dating their future partner by 30.
We know that the brain caps off its second and last growth spurt in your 20s as it rewires itself for adulthood，which means that whatever it is you want to change about yourself，now is the time to change it.We know that personality changes more during your 20s than at any other time in life，and we know that female fertility peaks at age 28，and things get tricky after age 35.
So your 20s are the time to educate yourself about your body and your options.So when we think about child development，we all know that the first five years are a critical period for language and attachment in the brain.It’s a time when your ordinary，day-to-day life has an inordinate impact on who you will become.
But what we hear less about is that there‘s such a thing as adult development，and our 20s are that critical period of adult development.But this isn’t what twentysomethings are hearing.Newspapers talk about the changing timetable of adulthood.
Researchers call the 20s an extended adolescence.Journalists coin silly nicknames for Twentysomethings like“twixters”and“kidults”.It‘s true.As a culture，we have trivialized what is actually the defining decade of adulthood.
Leonard Bernstein said that to achieve great things you need a plan and not quite enough time.Isn’t that true？So what do you think happens when you pat a twentysomething on the head and you say，“You have 10extra years to start your life”？Nothing happens.You have robbed that person of his urgency and ambition，and absolutely nothing happens.
And then every day，smart，interesting Twentysomethings like you or like your sons and daughters come into my office and say things like this：“I know my boyfriend‘s no good for me，but this relationship doesn’t count.I‘m just killing time.”Or they say，“Everybody says as long as I get started on a career by the time I’m 30，I‘ll be fine.”
But then it starts to sound like this：“My 20s are almost over，and I have nothing to show for myself.I had a better résuméthe day after I graduated from college.”And then it starts to sound like this：“Dating in my 20s was like musical chairs.Everybody was running around and having fun，but then sometime around 30it was like the music turned off and everybody started sitting down.”
I didn’t want to be the only one left standing up，so sometimes I think I married my husband because he was the closest chair to me at 30.“Where are the Twentysomethings here？Do not do that.Okay，now that sounds a little flip，but make no mistake，the stakes are very high.