Newly minted RHOC star and mom of three Emily Simpson talks to people about the ups and downs of having her sister carry her children

For Emily Simpson, the difficult parts of surrogacy are 100 percent worth every second she spends with her children.

PEOPLE’s Celeb Parents Get Real recently caught up with the Real Housewives of Orange County newcomer (who just joined the series’ cast for its 13th season), where she opened up about the experience of her sister Sara Moffitt carrying her three biological children: twin sons Luke and Keller, 3, and daughter Annabelle, 5.

“I have been very honest with my children, especially my daughter, who’s 5,” says Simpson. “She knows that her aunt carried her in her belly and that’s where she lived and then she was born.”

She continues, “I’m very honest and open because I just want them to know how they came to be and also not make it a big deal. Like, ‘That’s just what happened. That’s where you lived and then you were born and now you’re mine.’ ”

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Simpson admits that she considers it a downside that she never felt what it was like to carry her children herself, although she jokes the trade-off was totally worth it.

“I’m okay with that — obviously, the end result of having children is the most important thing,” says the reality star, who is also a stepmother to husband Shane Simpson’s two daughters Chanel, 12, and Shelby, 17.

“But there are times when I wish I knew what it felt like to carry my children in my body. And then other times, I’m glad I didn’t,” ” Simpson reveals, laughing as she adds, “It’s easier to let someone else do that!”

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Regardless of whose belly her daughter was born from, there’s no denying she is completely her mama’s due to her fiery personality alone.

“I call Annabelle ‘Karma’ because I’m sure that I was not an easy child,” Simpson tells PEOPLE. “That child paints all over everything — paints on the drapes, paints on the furniture, climbs the walls. So Annabelle is my karma.”