"It was the best wedding ever," Hilary Duff says about her wedding day with husband Matthew Koma

It’s been one month since Hilary Duff married Matthew Koma in an intimate backyard ceremony, and the Younger star is still on cloud nine.

“It’s been such a high,” Duff, 32, tells PEOPLE. “It was the best wedding ever. We had so much fun. We just kept saying, ‘That was the best day of our lives!’ ”

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Hilary Duff and Matthew Koma on their wedding day
| Credit: Harper Smith

A couple weeks after their Dec. 21 nuptials, Duff and Koma, 32, headed to South Africa for a romantic honeymoon.

“We did the coolest things,” says Duff. “We both had never been on safari and it was what everyone says it is. There are no words. We saw the big five (rhino, lion, tiger, elephant, buffalo) within the first two days! I felt so lucky.”

Hilary Duff, Matthew Koma
Hilary Duff and Matthew Koma on their honeymoon
| Credit: Hilary Duff/Instagram

Though the mom of two (she has son Luca, 7, with ex Mike Comrie and 15-month-old Banks with Koma) jokes that kids, “bring you down to earth.”

Says Duff: “I came home and I was trying to explain to Luca everything we saw and he was like, ‘But did you see an iguana?’ ”

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Hilary Duff and Matthew Koma on their honeymoon
| Credit: Hilary Duff/instagram

Now firmly back in her routine, Duff is focused on keeping her family happy — and healthy, partnering with cold and allergy relief brand Zicam. “It is clinically proven to shorten your cold,” says Duff. “And I understand the panic of being sick around kids — you feel so guilty even trying to get some sleep!”

As for 2020, “I have so many exciting things happening,” says Duff. “And I’m going to keep on trucking!”