We always tend to judge people by our own historical or cultural biases. "Back in the day" age difference mattered little sometimes.
My father was 20 when he met my mother who was 16 and began dating. Today, Child Protective Services would have been involved. My maternal grandfathe was in his 20s also when he met my grand mother who was also in her mid teens. My maternal grandfather's parents are another story. He was born sometimein the late 1800s and she was born in 1900 and gave birth to my mom's father at age 12.
Paternally there are similar stories. My grandfather was in his 30s and grandmother was a teen. Crazy times.