Jessica Simpson on motherhood

In the upcoming issue of People magazine, Jessica Simpson discusses her new role as a mother to her three-week-old daughter.

Simpson, 31, gave birth to her new daughter, Maxwell Drew Johnson, via C-section two weeks before her due date.

In the interview, Simpson discusses how her body has changed as a result of going through a pregnancy.

"After you have your baby it's like, 'Oh my God, what happened to my body?' This is not me," she said. "It would be nice to feel comfortable in a bikini, but that's not my goal."

To shed those extra pounds, Simpson has partnered with Weight Watchers and is eating more vegetables and proteins.

"I just want to fit into jeans!" she said. "I'm less concerned about how my hair looks or if my gut is showing.

But Simpson also wants to lose the weight before her wedding to Maxwells father, former NFL star Eric Johnson. The couple got engaged in Nov. 2010, but put the wedding plans on hold when Simpson became pregnant.

They plan to walk down the aisle in December.

"My life has completely changed," Simpson said. "She's my career at the moment. I know I was always meant to be a mom, and I think I'm doing a really good job. I'm the most aware I've ever been."