Chic and summery in her strapless dress on the Late Show With David Letterman last night, Nicole Richie looked better than ever. But underneath the pulled-together façade, the Simple Life star admits that she is frightened she'll follow in her co-star Paris Hilton's footsteps and be the next young Hollywood starlet to do jail time, for her December 11 arrest for driving under the influence. She pleaded not guilty in February and is expecting to hear the outcome by the end of this month. "I'm just keeping my fingers crossed. Of course, I'm scared," she told David. "I'm willing to face whatever consequences come my way. I take responsibility for what I've done." On the positive side, Nicole says, "I try to take everything that I go through as a life lesson and really try not to make the same mistake twice." So much for that 2003 misdemeanor DUI conviction!