Current age: 33
Career at 20: Nicole studied arts and media at the University of Arizona for two years before dropping out and returning to LA. She admitted to experimenting with drugs at this age and eventually did a stint at the Sierra Tucson drug rehab center after being caught with heroin. Fame wouldn't come until 22, when Nicole starred alongside her then-BFF Paris Hilton in the reality show The Simple Life.
Relationship status at 20: Nicole was linked to Cher's son Elijah Blue Allman before she began dating Adam Goldstein (otherwise known as DJ AM) in 2003.
Quoted: While Nicole didn't pop up on the public's radar until 2003, she recently reflected on her 20s in an interview with Ocean Drive magazine, saying, "The mistakes my parents made in their 20s weren't documented, and the mistakes that I made in my 20s were. I don't know anybody who can look back at who they were at 20 and say, 'I'm the exact same person.' It's all about evolving and growing."