As someone who has worked as an actress, singer, fashion designer and everything in between,Jessica Simpson‘s biggest and most important job has still been Mom — but it hasn’t always been easy.

“Three is challenging. We are trying to get into the groove and make sure all three kids are getting equal attention … it’s more than a full-time job right now,” Simpson, 38, tells PEOPLE of her and husbandEric Johnson‘s dynamic with their kids: daughtersBirdie Mae, 5 weeks, andMaxwell “Maxi” Drew, 7 next month, plus 5½-year-old sonAce Knute.

How she handles some of the more chaotic aspects ofparenting two children and a newborn? “The other night, all three kids were crying at the same time, so I just joined in! Ha!” Simpson says.

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Jessica Simpson on Easter

Birdie Johnson.Courtesy Jessica Simpson

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Jessica Simpson and daughter Birdie.Courtesy Jessica Simpson

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“[Birdie] makes our family complete,” saysthe new mom of three. “Someone once told me to keep in mind that everything is a phase with infants and kids … trying to remember that fact, and celebrate the small victories.”

“However,when this girl needs something, she makes it known!” the star jokes to PEOPLE.

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“We are trying our best to be as present as possible and enjoy every part of having a newborn,” she explains. “We know how fast the time goes and how precious it is.”

For more onJessica Simpson’s new life as a mom of three, pick up the latest issue ofPEOPLE, on newsstands Friday.

source: people.com