07/14/2008 at 07:00 PM EDT
Khloe Kardashian, the youngest of the Kardashian sisters, has been sentenced to up to 30 days in Los Angeles County jail for violating probation following a DUI arrest.
"She admitted to failing to complete [roadside cleanup duty] and enroll in an alcohol education class," said L.A. City Attorney spokesman Frank Mateljan on Monday.
Kardashian, 24, has until July 18 to begin serving her sentence. She was sentenced on July 3.
"Khloe is ready and willing to serve out her sentence, no matter how long and where, and have this resolved," her rep tells PEOPLE.
Kardashian, who appeared in E!'s Keeping Up With the Kardashians, was arrested for DUI in March 2007, and was sentenced to three years probation.
Over the weekend, Kardashian showed no obvious signs of worry about her upcoming jail term, as she attended a party at the Project Beach House in Malibu with her mother and sister Kourtney.
"Khloe actually looked great, really relaxed and having a good time," says a partygoer at Sunday's Lia Sophia Clambake. "[She] didn't look like she had a care in the world and even got a massage."