Kate Middleton Says Prince Louis Is ‘My Baby’ but Admits He’s ‘a Proper Boy Now’

• Kate Middleton can’t believe her youngest son is already four months old.
• Prince Louis joined his parents at the Platinum Jubilee celebrations last month.
• He made his Trooping the Colour carriage ride debut alongside his older siblings. The prince also had his first public speaking appearance under his belt. Prince George has been winning hearts all over the world.

Kate Middleton can’t believe her youngest son is already a “proper boy.”

Last month, the Duchess of Cambridge paid a visit to Little Village’s Brent hub, which is part of London’s largest baby bank network, and was smitten by a baby resting in a stroller. The mother of three children — Prince George, 9, Princess Charlotte, 7, and Prince Louis, 4 — made a remark about her own children’s development.

“I keep thinking Louis is my baby,” Kate said of her son, “but he’s a proper boy now.”

While Prince George and Princess Charlotte are quickly learning the royal etiquette by accompanying their parents to family gatherings and public appearances, Prince Louis is approaching the age when he can participate in public life. Prince Louis made a splash last month when he joined the royals at the Platinum Jubilee weekend celebrations, marking Queen Elizabeth’s historic 70 years on the throne. He already had his first public speaking appearance under his belt and mastered his royal wave.

Louis made his Trooping the Colour carriage ride debut alongside his older siblings, waving enthusiastically to the crowds and even showing off his salute. As planes flew overhead as the royal family gathered on the Buckingham Palace balcony, Prince Louis adorably covered his ears.

Prince Louis of Cambridge and Catherine, Duchess of Cambridge

Prince Louis and Kate Middleton | CREDIT: MAX MUMBY/INDIGO/GETTY
At the Platinum Jubilee Pageant, the little prince won hearts all over the world with his enthusiastic waves, animated faces, and interactions with his family.

“He’s a cheeky monkey — a typical third child,” a family member previously told PEOPLE. “It’s great that the rest of the world got to see him having fun.”

Kate and Prince William, both 40, have previously hinted that they will have three children. During a visit to Bradford in 2020, the Duchess of Cambridge revealed to royal fan Josh Macpalce that she is unlikely to become a mother of four in the future.

“I don’t believe William wants any more,” Kate explained.

Kate also has several pieces of jewellery that feature the initials of her three children.

But that doesn’t mean Kate has lost her attraction to babies! Kate has admitted that meeting with young children makes her feel “broody.”

“Could you please get my wife out of here before she starts crying?” In May, the couple paid a visit to a Scottish classroom where students were learning about empathy by observing an infant — a.k.a. their “tiny teacher,” Saul!

Can’t get enough of PEOPLE’s coverage of the Royals? Sign up for our free Royals newsletter to stay up to date on Kate Middleton, Meghan Markle, and other royals!

Kate met with parents and their babies during a visit to the University of Copenhagen on the first day of her solo royal tour in Denmark in February.

“It makes me feel very broody,” Kate admitted. “William is always concerned about me meeting children under the age of one. ‘Let’s have another one,’ I say when I get home.