[rdrey]

I have no data to back this up, but I would guess that college / university graduates also get married later in life.

[thedufer]

Based on the first Google result [1], average age of first marriage goes up by ~2.5 years for men and ~3.5 years for women with a bachelor's degree over just a high school diploma.

1 http://www.bls.gov/opub/mlr/2013/article/marriage-and-divorc...