Ashlee Simpson-Wentz Calls 2008 the Best Year of Her Life

By Mark Gray

01/03/2009 at 01:40 PM EST

Ashlee Simpson-Wentz would just as soon turn back the calendar and ride out 2008 a little bit longer than proceed on with the new year.

"I don't know if I can have high expectations for 2009 because 2008 was so good," she told reporters in Las Vegas before celebrating New Year's Eve at Pure Nightclub.

Joined by husband Pete Wentz, the new mom sipped champagne and enjoyed one of her first big nights out since giving birth to Bronx Mowgli Wentz in November.

Her son, however, wasn't far: He was napping in the hotel with a babysitter. "He's the best thing that ever happened to me," she said of the newborn.

Of 2008 – a year in which Ashlee got married and became a mom – she says: "It was the greatest year of my life."