She may not have been a first-time mom, but for Katherine Heigl, adopting her second daughter opened her eyes to an entirely new chapter in parenthood: life with a newborn!

The actress and her husband Josh Kelley welcomed their first daughter Naleigh, 3½, from South Korea when she was 9 months old, and recently adopted Adalaide Marie Hope shortly after her birth.

“I had never had a newborn before. I didn’t really have that experience. So it’s all been new,” the actress, 33, told PEOPLE at the 40th AFI Life Achievement Awards in Culver City, Calif. on Thursday.

“I was prepared for the nights and having to get up and all of that. But the beauty of it is it’s really only a few months of your life that you’re walking around like a zombie because you haven’t slept.”

Fortunately for the new family of four, things are continually getting “easier and easier” — due, in part, to one very proud big sister.

“Naleigh was super excited about having a new baby sister — until she arrived. Then she was a little hesitant about whether or not she wanted her to stay,” Heigl shares. “And then she became her little protector and is taking on the role of big sister very seriously.”

Still, admits the new mom-of-two, juggling her growing brood isn’t always smooth sailing.

“I think it’s far more chaotic than I anticipated,” she says. “And I think every parent probably says that and every parent tries to warn new parents about it. And we all go, ‘Pish posh, it’s going to be fine. What’s one more?’”

(Source)