Credit: Seth Poppel/Yearbook Library; Steve Granitz/

You've come a long way, baby!

Jennifer Aniston turns 43 on Saturday -- and, with a white-hot movie career and a sizzling, nearly year-long romance with Justin Theroux going strong, she's in her prime!

But long before she became a sitcom superstar on Friends (which debuted in 1994) and hot-bodied Girl Next Door with world-famous hair and a fascinatingly complicated love life (paging ex-husband Brad Pitt), Aniston was just another adorable, likable kid.

Born in Sherman Oaks, Calif. and later relocating to NYC with her parents (soap opera star John Aniston and mom Nancy Dow), Aniston was an athletic Manhattan private school girl with dreams of acting stardom -- even though one drama teacher called her a "disgrace to theater."

What would Aniston do if the acting thing hadn't worked out? "Professional waitress," she said during a 2011 Inside the Actors' Studio chat. (In her earliest days in Hollywood in the early 1990s, she waited tables, did telemarketing and other odd jobs to make ends meet as she starred in one failed sitcom after another.)

See what Aniston looked like as a little girl, pre-teen -- and check out her crazy prom hair and her high school pal Chastity (now Chaz) Bono! -- in Us' gallery now!