not really alarming - biologically speaking, it's fairly normal. ovulation starts at a young age (though this is getting lower and lower), but go back either a century or a millenium and you'll see that women were starting families at a very young age. life expectancy and quality of life was lower then.. perhaps due to women giving birth younger, perhaps not, but i wouldn't say that it's alarming so to speak.
in an age where the government wants to stick everybody in higher education rather than let them get on with manual labour in their local surroundings, that is, abolishing the working class so to speak (not that this is a good or bad thing), adulthood is something which many people don't truly enter until their mid-twenties, where as i just mentioned, it used to be early-mid teens.