The INSIDER Summary:

• Sources confirm that Blue Ivy is shaping up to be an "amazing big sister" to Rumi and Sir.
• Blue Ivy takes her job as big sister "very seriously."
• The Carters recently bought an $88 million mansion to be closer to Blue Ivy's school as she prepares to start Kindergarten.

She may be 5 years old, but Blue Ivy is already the sister we wish we had. According to sources for "People," Beyoncé and Jay Z’s daughter is shaping up to be an “amazing big sister” to the couple’s newborn twins, Rumi and Sir—and we can’t wait to see her in action. Per the magazine’s sources, Beyoncé and Jay Z were worried that Blue would feel “left out” when the twins arrived. The “Formation” singer was reportedly so concerned that she “made sure to spend lots of quality time” with Blue before she became a mom of three.

However, it seems like the A-list couple had nothing to worry about as sources close to the family told "People" that Blue is doing more than fine as an older sibling.

“There was no need to worry because Blue is great,” the source said. “She takes her job as a big sister very seriously and helps out a lot.” In fact, Blue’s been so good that she’s been able to pick up the slack a bit when her mom needs a rest. “Beyoncé has been very busy with the newborns, but she’s also been able to relax a bit,” the source said. “It’s helped her that Blue has been such an amazing big sister.”

However, the couple won’t have Blue’s help for long. According to People, the Carters recently bought an $88 million Bel Air mansion to be closer to Blue’s school as she gears up for kindergarten. And though Bey welcomed two newborns last month, she’s still reportedly experiencing the anxiety all moms feel when seeing their babies get older.

“Blue is excited about starting kindergarten,” the source said. “She misses her friends. It will be fun for her to get back to her own life at school. Beyoncé is excited for her too but keeps saying that she can’t believe Blue is starting kindergarten. She thinks Blue is growing up way too fast!”

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