Serena Williams is talking about the joys of being a mother to two daughters.

The tennis champion, who shares daughters Olympia and Adira with husband Alexis Ohanian, gushes the younger one is a

lot like her.

“Olympia was a solo child,” Williams, 43, tells PEOPLE.

“She was our star. And I am so obsessed with Olympia. Even when I was pregnant, I was like, ‘How do I even love anyone as much as Olympia? It just doesn’t work.’ ” 

William’s, who welcomed Adira in 2023, adds: “It’s so funny how, I don’t know, just your heart gets bigger. I was just like, my heart just got bigger.”

“Olympia is a very hard act to follow, but I tell you what, Adira has followed it and it’s just so crazy,” Williams tells the outlet.

“She’s amazing. I just can’t wait for people to see how amazing she is in her own way. And she’s so special and she’s so tough. She’s just a tough little cookie. And she reminds me a lot of me in that aspect.”