Lisa Stelly Osbourne Is 'Really Happy' She Has Only Girls: 'Pink, Princesses and Tutus Everywhere'

Lisa Stelly Osbourne‘s not getting much sleep these days.

It makes sense since she’s a 31-year-old mother of three kids under 7, just starting her new business and also going through a divorce from estranged husband Jack Osbourne.

The Fancy Sprinkles founder — who shares daughters Minnie Theodora, 9 months, Andy Rose, 3, and Pearl Clementine, 6½, with Osbourne, 33 — recently sat down with PEOPLE to discuss how her latest venture is taking off and how it’s affecting her parenting style.

She started off with how she got into the cake-decorating business to begin with, explaining that it was never an aspiration. “About two years ago … I decorated a cake for Pearl’s birthday and she wanted a specific type of cake and I had no idea how to make cakes,” Stelly Osbourne tells PEOPLE.

“I started watching all these YouTube videos and realized there was this whole world out there of … people making all [this] beautiful art with fondant and icing as their medium,” she explains, adding that she had to overcome her own talents to start her company.

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Lisa Stelly Osbourne

Lisa Stelly Osbourne

“I’m not a great baker, actually,” Stelly Osbourne admits. “I use box cake mixes and make my own frosting, but I’m not so much into the baking as much as the decorating part. It changed my world forever and you can actually eat it! It was a good way to incorporate my love of cake decorating with my children.”

“I started my business [because] I was looking for a specific type of sprinkle, a plain white star … ” she continues. “I went to three stores and looked online but couldn’t find the most basic thing in the world, in my mind.”

Her trick for the best-looking bake-sale goods? “Yesterday, we had a bake sale,” recalls the mother of three. “I didn’t have time to bake anything fantastic so I went to the store and bought cupcakes and put frosting and sprinkles on them. I like to think that my baked stuff stands out at a bake sale. You don’t need to be a great baker or decorator to simply make a plain cupcake and put Fancy Sprinkles on it, and it looks super high-end.”

Andy and Pearl Osbourne

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It’s no surprise she didn’t have time to make anything from scratch, as she’s “had to lose more sleep” since starting her business. “I get up really early and spend a good time with the kids before they go to school and I set my work day for a certain amount of time to be at the office,” she says. “I try to get back home in time to pick up the kids from school and spend that quality time with them before they go to bed. It’s more about quality than quantity.”

After raving about how she makes sugar cookies and gingerbread houses with her little ones annually (this year they’re using Fancy Sprinkles, of course!), Stelly Osbourne dished on her favorite part of being a mom of girls.

“People online leave comments like, ‘Don’t you wish you had a boy?’ I’m like, ‘No!’ No way, I love my girl squad,” she says with a laugh. “There’s pink, princesses and tutus everywhere. They’re so full of love. I’m really happy with the way that everything turned out with my kids.”

Stelly Osbourne’s three daughters are all hitting new milestones lately, especially the younger two. Andy, her mom says, absolutely loves to swim and is already excelling after only six months of classes. And Minnie is crawling, scooting and eating solid foods.

Pearl, Jack, Andy and Lisa Osbourne

In May, Stelly Osbourne filed for divorce from Osbourne, three months after they welcomed Minnie. At the time of filing, Osbourne shared an Instagram post on behalf of the pair, explaining that while the news of their separation “has probably come as a bit of a shock to everyone,” the couple tried for years to make their marriage work.

“What’s best for our family right now is that we separate lovingly, and remain best friends who are committed to raising our children together,” the former reality star wrote on Instagram. “We are disappointed but feel confident that we will continue to grow our relationship as co-parents and best friends.”

The former couple exchanged vows on Oct. 7, 2012, in front of 48 close friends and family members, including his parents Sharon and Ozzy Osbourne, as well as sister Kelly Osbourne.