Jessie James Decker -- Good Genes Or Good Docs?!

Jessie James Decker's looks over the years 'Look So Good!'

Here is a 21-year-old version of the country singer with her brunette locks pulled back at a nonprofit event held at the Ryman Auditorium in Nashville, TN back in 2009 (left). This was the same year she debuted her first album, featuring her hit song "I Look So Good (Without You)."

And 13 years later ... this hot 34-year-old momma recently showed off her freshly highlighted 'do at the American Music Awards in Los Angeles. She definitely knows how to work the camera!

Decker the halls!

The question is ...