Can someone please explain why a 14 year old are more mature than a 18 year old?

When plants are rooted in different places, they grow at different speeds. There is no way to look at a person or hear them and know where they are planted.

You answered your own question when you said “he”. 🤷🏻‍♀️

Maturity is about life experiences and some people just... don't have any and so stopped developing when they were 12 or whatever. I know 14 year olds who I'd consider more 'mature' than some 50 year olds.

If the 14 yo is a female, then that is why. Males take longer than females to mature. Although, every man I know will giggle like a school girl over a fart.

It’s all subjective. How they’re raised, their social exposure, life experience, mental and emotional development all come into play. Now that I’m a bit older I realize that 4 years is not that big of a deal.

Most of boys mature later than girls, specially at that age renge.
As a BTW comment, I know SOME woman that never went beyond their 14-18 years old emotional maturity.

Grew up in a different environment and experience more things to either make one mentally grow or not.

I know pensioners who are more immature than the average twenty year old.

Not acceptable, but it is something we can't do anything about, and have to learn to live with it or ignore it. He is simply immature, arrogant and also ignorant, let him remain in his bliss.

It is embarrassing for all of us who have anything remotely in common with him.

Who said it is acceptable?

"Oh god!"

some people never grew up

Age does not always equal maturity 😒

Everyone is unique.