All hell is going to break loose — at least that’s what Sofia Richie and Scott Disick are predicting once they officially announce their engagement. Family members on both sides are horrified by their relationship, especially Scott’s ex Kourtney Kardashian.

Sources are revealing exclusively to Life & Style that the KUWTK star feels betrayed by longtime Kardashian friend Sofia, 19, and her 34-year-old baby daddy. “Kourtney thinks she’s too young to be dating Scott and playing stepmom to their kids [Mason, 7, Penelope, 5, and Reign, 2],” says an insider. In case you forgot, Sofia’s older sister is Nicole Richie, who went to school with Kim Kardashian — who was also really close to her BFF Paris Hilton.

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Also joining Kourtney in speaking out against the May-December romance is Sofia’s dad Lionel Richie, who previously admitted he is “scared to death.” The new American Idol judge has “accused Scott of being a bad influence on Sofia,” adds the source. “Lionel’s terrified she’ll be led astray by Scott.”

While Kourtney, 38, is hesitant to let her kids around Sofia, she is moving on with a younger man of her own. The brunette beauty is expecting her first child with 24-year-old model Younes Bendjima — but she is no rush to get married. “Though she loved Scott and wanted him to commit, she was never desperate to walk down the aisle,” a source explains. “She adores him and thinks he’s much more mature and responsible than Scott ever was, but she still doesn’t want to get married, at least for now.”

Despite the tension, Scott is happier than ever with his new fiancée and ready to settle down. “He claims to be a changed man,” says a source. “He’s much more well-behaved with Sofia.” The source continues, “Despite the huge age gap, he feels that Sofia is the only person who understands him.”

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