It’s tough because I think generalizing men as slower to mature than women isn’t the whole story, but I’d be lying if I said that I didn’t notice some of this in everyday life. All of the girls I know in that 23-29 age range (whether it’s my sister, female cousins or friends), seem to have their lives in order, and are much more accomplished than the guys that I know in that age range. The girls are college educated, and most if not all of them have promising careers, such as financial analysts, lawyers, (med school to become nurses/doctors), etc. The guys in that same age group that I know might be employed, but most work meaningless jobs, or are unemployed all together.
I definitely think that guys nowadays in their 20s are slower to get their lives together than girls are, and a lot of them are aimless and lack ambition and drive. Maybe something flips for them in their 30s, but a lot of guys are clearly behind girls now when it comes to education, drive and ambition. Some of the girls that I know in their 20s either refuse to date guys in that age range, or actually prefer older men, who have their lives together.