Brooke Shields speaks candidly about the endless anxiety that often accompanies being a parent.

In an exclusive interview with People, the model and actress admitted that she thought she would feel "relieved" after her two daughters turned 18 and left the proverbial nest.

Instead, she realized what countless childless vacations have taught her over the years: parents never stop worrying about their children.

"When I go on vacation, all I can think about is where my kids are and what they are doing. It's like there's really no relief," she told the publication." It's like people say, 'Oh, that's going to be great. Once he can walk, we won't have to carry him everywhere. And they'll be able to walk all over the place and worry about falling off the stairs or the pool or the street."

"With every step you take, you'll feel safer now," she continued.

"And then a whole new worry will smack you in the face."

This fall, the model and actress' youngest daughter, Grier, will go off to college, and Shields and her husband, Chris Henchy, will officially be "empty nesters." Shields told "People" that she thought she would be "relieved," but now that both of her children are grown, she is "not ready."

"It's so foreign ...... to no longer live in a house 24/7 with the people who raised you. It's like going to a totally foreign place," she explained.

"What is the expression 'Wearing your heart on your sleeve'?" Shields added. 'This is like a hard suit. A full-body suit of heart."

Shields says that while children are prepared to deal with a whole new set of concerns once they venture out into the "real world," parenting adult children gives them the opportunity to see a different and new side of them.

"I said to my younger daughter, 'Give me a little grace period because I need to get to know you. Ever since the day you were born, I have been telling you when to sleep, when to wake up, when to eat, what to eat and what not to eat, what to say and what not to say, how to dress and when not to dress. And I have, in a way, been in their every single thing," she told the magazine. [And they start exposing their individual selves to you. And you have to realize, 'Oh, this is a human being,'" Shields continued. "I told my daughter: 'You only know how you look doing what I tell you to do. You are no longer a baby. And I need a little time to get used to you again as a young woman."