This is totally wrong. Many 26 year olds are well into their careers by then and have garnered a wealth of experience. A perfect example can be found in the porn industry. (sorry, I felt compelled to go there.)
Not many 26 year-old people have a PhD either.
At 18/19 you start university. Four years later (but actually probably 5 or 6 years later if you are average) at age 22/23 you start the MA. Two years after that you can start a PhD 24/25 The PhD takes anywhere from 3 to 6 years.
In some fields, education for example, they actually prefer PhD candidates have some outside experience and don’t like and sometimes will not accept the people going straight through.
Almost nobody, not even my really smart, super organized, incredibly focused wife gets a PhD at 26. 28/29 is about as young as you normally see and generally more like 31/32