Jessica Simpson, Eric Johnson, and Maxwell Johnson on July 4, 2012. Credit: Twitter/Supplied by XPOSUREPHOTOS.COM

Never too old for a birthday party!

Jessica Simpson turned 32 on Tuesday and celebrated her big day with loved ones.

A source tells Us Weekly that Simpson enjoyed a birthday lunch at Polo Lounge in Los Angeles with fiance Eric Johnson, their two-month-old daughter Maxwell Drew Johnson and close girlfriends.

The group popped some champagne and dined in a covered outdoor patio. They even sang Simpson "Happy Birthday." The source tells Us, "There was a lot of laughter coming from the table and everyone looked very joyous."

Amongst the attendees was Simpson's former assistant and Maxwell's godmother, Cacee Cobb. Cobb tweeted Tuesday, "Happy Birthday Jessica Simpson! I love you with all my heart."

The new mom wore a long flowy dress with long sleeves and big sunglasses for the celebration. Johnson, also 32, wore a blue button down shirt and jeans while baby Maxwell, who wore a little flowered top and shorts.

The couple got engaged in November 2010 and welcomed Maxwell, their first child, on May 1 of this year. For her 31st birthday last year, Johnson surprised Simpson with a bright orange Birkin bag (with an estimated retail value of $15,000).

"Eric made my birthday!" Simpson tweeted last year after receiving the designer bag. "I have never been more surprised in my life! Jackie O who?"