"We're not very formal people, so we're going to keep it easy and fun," she says

Credit: Courtesy Haylie Duff

They shouldn’t arrive barefoot, but if they end up that way, all the better!

Haylie Duff is finally in the thick of wedding planning. And while she has said it won’t be super casual, she does want her guests to feel comfortable ditching the formalities – literally.

“We want it to be something that everyone has a good time at, and if your feet hurt in your heels take them off!,” the actress, blogger and cooking show host told PEOPLE Monday at a 10th anniversary Napoleon Dynamite reunion in Los Angeles.

She adds: “We’re going to keep it easy and fun.”

Duff, 29, got engaged to Matt Rosenberg on April Fools’ Day (no, it wasn’t a joke!). But they’ve both been busy since – she has a new Cooking Channel show based off her blog Real Girl’s Kitchen, and he has a new apparel line – and are only now properly planning the wedding.

And yes, little sister Hilary is helping out.

“She’s about to start her show, as well, in New York,” Haylie says. “But yeah, she sends me ideas, and we’ve been going back and forth on some things. It’s great. It’s crazy!”

The other thing Haylie is fairly certain about so far is that the wedding will be in California. But she’s hard at work on all the other details.

“On my flight back from New York last night, I spent the whole six-hour flight looking at venues and looking at dresses,” she says, “so it’s starting now, which is very exciting.”

Haylie Duff Is Engaged!