Stephanie Pratt has pleaded not guilty to a misdemeanor DUI charge in a Los Angeles court Friday and will enroll in a 30-day rehab residential facility.

The Hills star, 23, was arrested back in October in Hollywood after driving home from fellow castmate, Holly Montag‘s birthday party. Her two breathalyzer tests registered .08 and .09 — the legal limit is .08. She was arrested and released on $5000 bail.

She recently told PEOPLE that the arrest “was the worst thing to happen to me and, at the same time, it was the biggest blessing” as a life lesson. If convicted, Stephanie faces up to six months in jail and a $1,000 fine.