Age of first time mothers vs women over 25 with high educational attainment

This week we take a look at the average age of first-time mothers and share of women over 25 who have completed some college or more over the years in the United States. 

As you can see the average age of first-time mothers has increased from 22.1 years old in 1970, to  26.9 in 2018. One of the most prominent contributors to this rise has been the ever-increasing share of women who pursue high educational attainment. According to this article in the New York Times,  "women with college degrees have children an average of seven years later than those without". On that front, the percentage of women who have completed some college or more has gone from a low of 18% in 1970 to an impressive 62.6% in 2018 (and 63.5% in 2019, which I did not include in my graph). On the contrary, the share of women who have not completed High School is down to an all-time low of 9.5% in 2019 compared to 39.8% back in 1970.  What are your thoughts on the matter? 

Source: United States Census Bureau, Data Tables, Educational attainment, United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2007-2018, on CDC WONDER Online Database, September 2019