It’s wild to think that Mary-Kate and Ashley Olsen were just 9 months old when they were cast as Michelle Tanner on Full House. The typical 9-month-old is barely mobile, barely talking, and here were these two babies pulling a paycheck. For the next eight years, they grew up with the show, as did their TV sisters Jodie Sweetin and Candace Cameron Bure, but the twins grew up differently than they did, Sweetin says. She explained why Mary-Kate and Ashley never got to be “normal kids.”Jodie Sweetin was 5 years old when she began portraying Stephanie, the precocious middle daughter of Bob Saget’s widower Danny Tanner. Candace Cameron Bure, who played DJ, was 11. The ABC sitcom spanned a huge chunk of the child actors’ lives, but Sweetin says there was a big reason the Olsen twins had a different experience. She told SheKnows:When Mary-Kate and Ashley started getting popular, they were doing movies, songs and all of that. They didn’t get a break.After literally watching the Olsen twins grow up in front of their eyes — from infants to toddlers and finally elementary school-aged children — audiences simply could not get enough of the adorable sisters. And their parents were apparently happy to keep them busy. During breaks from filming Full House, Mary-Kate and Ashley began starring in films together, including How the West Was Fun and To Grandmother's House We Go. When the sitcom wrapped after Season 8 in 1995, the Olsen twins continued to work, and ultimately the sisters acted together in more than 30 films, per People.That was a different experience than Jodie Sweetin had as a child actor. She got breaks from acting when Full House wasn’t in production, and her dad continued to work so that the money she earned from acting wasn’t the family’s primary source of income. For Ashley and Mary-Kate Olsen, however, Sweetin said:They worked all the time and they didn’t get the chance to just be normal kids in the way that I did. I had parents that really protected me and didn’t want money or fame. That wasn’t necessarily the case for the Olsens.When you look at how hard the sisters worked as children — on top of the fact they were just 8 years old when Full House ended — it’s a little easier to understand why they eventually got out of acting and why they declined the opportunity to return for the spinoff Fuller House in 2016.While John Stamos (aka Uncle Jesse) has admitted he was “angry” with the twins for rejecting the on-screen reunion, Bob Saget had a more gracious perspective. He said he loved his TV daughters but people should do what they want to do, and acting was not what Mary-Kate and Ashley wanted to do.Jodie Sweetin has talked before about the Olsen twins and “how hard they were worked” as child actors, and how she feels bad that they lost out on their childhood. Because they’re so private, we don’t know how Mary-Kate and Ashley feel about it, but they definitely cared enough about their TV family to attend Bob Saget’s funeral in 2022 and even released a rare statement.Mary-Kate and Ashley Olsen’s childhood may not have been “normal” by our standards (or Jodie Sweetin’s), but hopefully the fun they seemed to have on the Full House set was real. All eight seasons are available to stream with a Hulu subscription.