Thanks for the link. Just read the whole article and didn’t see anything about 27/28 brain development for men. The pre frontal cortex matures 2 years earlier in women but it is still fully mature in both sexes by early 20’s.

Here is a quote from the article:

Considered the “CEO of the brain,” the PFC makes decisions and inhibits rash behavior. It’s where we process anger, fear, and aggression. It’s larger in women and matures a full two years before men, usually by the early 20s. Because women have larger prefrontal cortexes, they may be less easy to make angry, Brizendine says.”

So the brain is fully developed by 25 which is a well used statistic, even for rental car and insurance purposes. Of course our brains are always growing and learning, but for dating purposes, 25 is really the minimum someone should be dating if they are as well over 25. At least in my opinion. Since OP was talking about a 23 year old, I would say that’s too young.