We're always being given age markers when it comes to life milestones, whether it's the age to have your first child if you want more than one, the best age to get married, and the ages we 'peak' when it comes to life satisfaction, relationships and salaries.
There's also the age that Brits feel like proper adults - but what do the experts say?
Professor Peter Jones, from Cambridge University, said: 'What we're really saying is that to have a definition of when you move from childhood to adulthood looks increasingly absurd.
'It's a much more nuanced transition that takes place over three decades.
'I guess systems like the education system, the health system and the legal system make it convenient for themselves by having definitions.
'I think the system is adapting to what's hiding in plain sight, that people don't like (the idea of) a caterpillar turning into a butterfly.'
He added: 'There isn't a childhood and then an adulthood. People are on a pathway, they're on a trajectory.'
So if you're in your twenties and you're stressing about adulting, don't. But if you've left your thirties behind and still don't think of yourself as an adult, equally - who cares?
Apparently, we'll also all turn into our parents eventually, too.
Dr Julian De Silva also added: 'We all turn into our parents at some point in our lives - and that is something to be celebrated. Becoming parents is the main trigger and lifestyle factors are also important.'
We'll leave it up to you to decide whether or not you're happy with that nugget of information.
