Maybe so as Brittney Spears and Paris Hilton are 24, are they responsible to be mother's at that age??? I don't think so, maybe 40 years ago 24 yr olds could handle that kind of responsibility but not in today's age. First many cannot even afford to move out of there parent's house.
Older parents make better parents IMHO.
Fertility has nothing to do with "maturity" you don't have to like it, but that's when women's fertility is at its peak. And the reason most 24 year olds today can't handle life frankly is because their parents didn't do a very good job raising them IMHO.