When it comes to having children, there is a serious social stigma that surrounds the idea of having a child too young. Young mothers (i.e. late teens and early twenties) are often categorized as irresponsible for landing pregnant, immature (meaning they aren't prepared for their role and its associated sacrifices), and incapable of raising children properly given they aren't too far off from being children themselves. Not only that, but society's image of motherhood is one of inconvenience and in that sense should, therefore, be postponed so that you can enjoy the excitement and freedom that is associated with young adulthood. Is it really fair, however, to assume that age automatically gives you a one up on the parenting scoreboard?
Speaking in biological terms, according to Carlo Bellieni, M.D., "the less risky range of maternal age to bear babies is 20-30 years". From fertility's standpoint, having children young (but not too young) is optimal for reducing the risks of miscarriage, preterm labour, congenital defects, and stillbirth (among many others). 100 years ago, it wasn't uncommon to see a 21-year-old woman married with one child, or at least one on the way. It was accepted as the norm and often viewed as strange if a woman in her thirties wasn't already married with children. (It's crazy to think of that sociological viewpoint nowadays, isn't it?)
Fertility aside, the advantage of having babies around the 30-year mark is the level of overall happiness that surrounds the role of being a mother. In a study of Effects on Maternal Age on Parenting Role, researchers Irlene S. Ragozin, Brooklyn Basham, et al., discovered that "increased maternal age was significantly related to greater satisfaction with parenting, to greater time commitment to that role, and to more optimal observed behavior". So, although a 20-year-old and a 33-year old, for example, may develop the same skill set of caring for children, the 33-year old is more likely to experience less hardship and struggle and is, therefore, more likely to enjoy motherhood. Needless to say, this shift can have a positive effect on children.
In saying that, while this might be true in some cases, in some cases it is not. Being happy in a role, whatever that role may be, is purely dependent on interests and priorities. The love of being a mother is entirely based on the person, not the age, and there are so many variants to people's personalities and capabilities, just as there are so many variants to the 'proper' maternal age around the world. Truth be told, no one is really prepared to have their first baby, no matter what age they are. What's important is that we take life by the reigns and guide our children as best as we know how, supporting each other in the process.