But us? We're fully grown adults living in a state of suspended childhood. So what happens in 20 years when we're all nearly middle-aged? What happens when millennials grow up?

We share apartments with people we don't know or with our parents, live hand-to-mouth, and subscribe to a culture of anxiety. We struggle with self esteem and live our social lives online. We know what we should be because we learned it from our parents, who got married when they were our age and had kids, a mortgage, and a hatchback just a few years later.

Basically, if you thought being in your 20s was high pressure, look forward to the latter end of your 30s and your early 40s. Bourne thinks we'll hit a point in our so-called middle age and realize the gravity of our situation. "The risk there is that a lot of people in our generation will get into their 40s and panic that they really haven't got enough accumulated assets to live on in 30 years time when they retire," he explains. "So you'll get a lot of people worrying in their 40s that they might not have a particularly happy retirement."

We're broke now, and we're likely to be living hand-to-mouth in later life, too. Ryan Bourne, head of Public Policy at the Institute of Economic Affairs , says that our generation will go into our 40s with far less accumulated wealth and be much poorer than we should be. "This lack of wealth is partly because millennials won't own housing, but partly because they'll have always paid so much for rent that it's quite difficult to save anything to even build up to a pension, or savings and investment. That is a big problem." Generational expert Jason Dorsey agrees: "We're expecting to have people in their 30s and 40s still relying heavily on their parents—30-somethings who still live at home and 40-somethings whose parents still pay for their cellphone bill. That phenomenon is putting pressure on the older generation. Unless income increases dramatically, we'll be in trouble."

But really, it's uncharted territory; no one really knows. Of the tens of academics, scientists, and economists I emailed, most didn't want to hypothesize—although in many ways, this unsavory tableau probably isn't too far off the mark.

At this age, because we're not able to afford having children, we'll be looking to have them in our late 30s and early 40s. "Having kids in your late 30s is more difficult and higher risk, and we believe there is going to be a lot of pressure around that time to get married and have kids," says Dorsey. "It's a perfect storm. The mood will be: If you are going to do it, you have to do it now. And, for the obvious reason that it's going to be more difficult and more challenging, it's going to create a different kind of conversation. You may end up with people having less kids overall, because if they start later maybe, they can only have fewer."

"The problem is we'll still chase many of the same things that other generations want, but it's more out of reach," explains Dorsey. "As our cohort enter their mid-to-late 30s, it'll be an interesting time to see if millennials achieve this idea of adulthood." VICE readers' number one fear is not finding love, which suggests we're not completely put off the idea of marriage, and our anger at the housing crisis shows—somewhat unsurprisingly—that we still value having a secure place to live. As we wait for these traditional markers of adulthood going into our 30s, said Dorsey and others I spoke to, we're likely to continue to be frustrated and unhappy.

Will we ever catch up to our parents' standards of living and accumulated wealth? According to the economists I spoke to, probably not.

No one would ever be able to predict what our mental health and well-being will look like in 20 years, but it's likely that we'll remain a generation characterized by anxiety and mental health—particularly considering our openness when it comes to discussing these topics. But we should be concerned by the prevalence of mental illness in our 20s. As a general rule, the quicker mental-health issues are dealt with, the more likely you are to recover and have better or better-managed mental health in the future.

Dr. Carole Easton—chief executive of Young Women's Trust , which supports and represents women aged 16 to 30 struggling to live on low or no pay in England and Wales—is particularly concerned for the future of women. "The reason women will struggle more, in our view," she says, "is because over their lives they'll get paid less, they're more likely to be stuck in low paid and insecure jobs, and, importantly, they're more likely to be the main carers for family members."

The psychological burden of that will lay with women—some of whom will find they can't have children—but it'll be felt throughout society. As Dr. Amy Kaler, professor of social structure at the University of Alberta, told VICE , if women stopped having children, "We'd first notice the collapse of economic activity that requires young children and parents, stores for babies, nannies, day cares. Then an upward ripple in elementary schools, kids' sports. We'd also become completely dependent on immigration to continue to exist, as a country. We'd see more efforts to attract immigrants—young immigrants—to bring more people in."

What mental-health professionals are concerned about is that we don't know the long-term effects of living in our "suspended adolescence." Lucy Lyus at mental-health charity MIND says, "We know that everything happening to young people at the moment contributes to a lack of well-being and can lead to anxiety. Obviously it's worrying to know what is going to happen when this generation grows up." Lyus adds that none of these contributing lifestyle factors are going to change soon. It's in the balance: If we want to improve the future mental health of millennials, changes need to happen now. "We know that the government will say that they are committed to making mental health as much of a priority as physical health, and have committed a billion pounds over the next five years to make that happen," she says. "But we don't actually know how it's going to go."

"Leaving symptoms untreated can not only result in unnecessary suffering for the individual, but interfere with building a rich and meaningful life moving forward," says clinical psychologist Dr. Lisa Orban. With regards to the anxiety millennials report in their 20s, she says, "The brain is still malleable in young adulthood, and exposure to stress in one's environment early on can have an impact on the course of one's mental health. If young adults learn how to identify stress and develop adaptive coping strategies early on, chances are they will be more proficient at handling stress, which can prevent or mitigate mental-health symptoms in the future."

At least in our miserable middle age we can look forward to a long retirement, right? Not exactly. We'll work longer than any generation yet, partially because we'll be supporting the children we had late in life until much later—an issue compounded by the fact the government is hell-bent on us working right up to the brink of death. "The state pension age is going to have to rise dramatically for us because of an aging population," explains Bourne. "The government essentially introduced this triple-lock mechanism that makes the state pension even more generous, and that makes no sense when you've got an aging population. Something's got to give on that, and the most obvious thing to do would be to raise the state pension age very substantially."

Already retirement ages are scheduled to rise to 66 in October of 2020 in the UK and, under current government proposals, 67 between 2026 and 2028, and 68 between 2044 and 2046. We don't know how much higher those could go.

This all sounds very doom and gloom, but conveniently we as a generation don't exist in a bubble. We can't be ignored, and these issues—housing, lack of savings, mental health, and so on—left to fester. Eventually the knock-on effects will become a burden and our social and financial issues have to take priority. "The contemplation of what's going to happen if we don't fix all of these problems is almost too awful to think about," says Rachel Laurence from the think tank New Economics Foundation. "I think if we really don't fix most of them, there will be a major economic crash and a massive depression. But I hope that with the huge number of people moving into the second and third phases of adulthood with these situations, this is a tipping point."

As Laurence points out, our whole economy is powered by debt. If a generation isn't able to buy mortgages on properties for them or their children, while wages stay stubbornly and unfairly low and the economy grows, it's a "ticking time bomb" situation.

When will we leave our extended adolescence? Does dealing with all this mean we will have finally grown up by the time we're through the worst of it, if we ever even reach that stage? Dorsey predicts that we'll feel like we've reached adulthood when we're about 40—and I'm inclined to agree. But all we do know with certainty is that what "adulthood" means and how it is defined will completely change with our generation.

Passing 18 could soon mean nothing—just an excuse for a party and the ability to buy a drink without fake ID. And many more traditional markers of adulthood could also be abandoned; "being an adult" might not mean owning a home or having a child any longer. Just as our parents set the parameters for our idea of what adulting was, we'll decide what being an adult means for Gen Z and beyond.