Jennifer Aniston -- Good Genes Or Good Docs?

Aging is definitely a friend of Jennifer Aniston.

Here’s a 23-year-old version of the "Friends" actress at a party back in 1992 (left) and 24 years later ... the hairstyle connoisseur -- who celebrated her 47th birthday earlier this week – on the red carpet in Los Angeles last month (right).

"Just Go With It."

The question is …