There are many factors to take into consideration when deciding what age is the best age to start a family. The overall trend in the U.S. in recent decades has been to have one's first child at a later age than in previous generations. I am probably among the minority, but I was a full decade younger than my mother and twelve years younger than my father was than the age at which my parents were when I was born.
Financial considerations seem to rank high for many couples when deciding when is the perfect time to start a family. Although financial concerns are important to consider, they should not be the lone deciding factor. There are many other issues to consider such as health of the mother. If you choose a conventional treatment route during pregnancy and delivery, a mother having her first baby at age 35 and beyond is quickly labeled as being of an "advanced maternal age." This easily contributes to an abundance of additional testing and prenatal care that younger mothers don't typically have to worry about.
Another consideration is the age and status of you and your spouse's own parents. Having a baby at age 24, my father was already deceased for 5 years, so my child's grandparents were already limited to three even prior to being born. Waiting until age 40 to have my first child could have possibly resulted in no living grandparents or older extended family members. I might be the youngest mom at the playground and dance lessons, but I am ironically not the mom with the youngest parents. Mothers who are a decade or more older than me often have parents the same age as my mother.
Career concerns are another important consideration to address. Many parents desire to have a decade or more invested into a career before taking time off to have children. Often, though that decision becomes the motivating factor behind not being a stay-at-home parent.
It would seem that parents who wait to have children until they are older would be more likely to have at least one parent stay at home (at least for a few years) because they presumably have achieved a greater degree of financial security and can survive on one income. Often, what happens is that parents who spend years working before starting a family have become accustomed to the lifestyle they have created based on two incomes and are reluctant to give up one income. The only foreseeable way to ensure a transition from two incomes to one income is to make lifestyle choices based on one income well before children come along. Otherwise, even individuals who have some desire to stay at home often change their minds and continue working because of the dependence they have created on a lifestyle of which they have grown accustomed. Also, once you have several years invested in a career, giving it up might be difficult because you are faced with the realization that it might be more difficult, if not impossible, to pick up where you left off.
Another consideration, though, is whether or not other family members or friends are having children. Being the only couple having a baby in both my husband's and my family was a very difficult adjustment because the demands placed on your time and divvying up holidays becomes problematic. Adults are eager to have a holiday filled with children's laughter, and there are no other children to share their time with. So, all of the burden falls on the only family members who have children, which was us.
Another important consideration is child spacing. If you wait until an older age to have your first child and want several children, there will be very little spacing in between children. That shortens the time spent breastfeeding. For my own personal circumstances, having my first child early allowed me to breastfeed for the length of time I chose and allowed for true self-weaning. If I felt pressured to wean my child by 18 months or two years in order to prepare for another pregnancy, I would be resentful of that hurried pace of trying to conceive again. When you have your first baby at a younger age, you can leisurely space your children out. Your toddler will not have to share the spotlight with a sibling. Oddly enough, though, having only one child causes more interference from extended family members. If you have at least two children, relatives are less likely to place demands on your time because you are instantly viewed as a "family" once you have more than one child. If you have one child, you all too often are unfortunately viewed as two adults who live with a kid.
If you don't mind being the only family member with a baby and you don't mind being the youngest parent (not to sound overly enthusiastic) wherever you go, then having your first baby in your twenties might be a choice to consider.
The age at which women begin having children is increasing well into their thirties. That is why it is beneficial to provide you with some often overlooked considerations worth evaluating from the perspective of a twenty-something parent. There is obviously no one perfect age for everyone to start a family, but considering more factors than finances is imperative when making a decision. In our consumer-oriented culture, we, all too often, are excessively preoccupied with financial considerations that we fail to look at the big picture.