Gwyneth Paltrow attends The Tracy Anderson Method Pregnancy Project on October 5, 2012 in New York City. Credit: Dimitrios Kambouris/

Gwyneth Paltrow is happily over the hill.

The Academy Award winner (and mom to daughter Apple, 8, and son Moses, 6, with husband Chris Martin, 35) celebrated her 40th birthday September 27. At pal Tracy Anderson's Pregnancy Project event supporting Every Mother Counts in New York City October 5, the Iron Man 3 actress spoke about what the milestone birthday means to her.

"I was really worried about it, leading up to the day, but now I feel really happy and content with my life," Paltrow told reporters. "I'm excited to move into the next phase. It's much more exciting than I thought it would be."

Paltrow doesn't predict much will change now that she's entered a new decade. "I think I try to promote self-growth and reflection for myself every day," she explained.

Despite her luxe lifestyle, Paltrow -- whose BFFs include Cameron Diaz, 40, and Beyonce Knowles, 31 -- said she's just like any other mom. "We have a scrimmage soccer game in our yard every day after school. It's so fun," she said. Though Moses prefers soccer, "Apple has been really loving gymnastics," the star said.

Regardless of the activity, Paltrow is glad her children are being actively challenged on a daily basis. "I feel that mental happiness and physical happiness are so closely related, and especially for kids, because they have so much energy."