"Our daughter isn't even 4 months old and she's already more badass than I'll ever be," Broadway star Patti Murin said
Patti Murin daughter
Credit: Patti Murin/Instagram. Inset: Cindy Ord/Getty

Patti Murin is speaking from the heart about her daughter's open-heart surgery.

Posting to Instagram on Saturday, the Broadway star, 40, shared a lengthy post about how her daughter Cecily Philips previously underwent open-heart surgery at 10 weeks old.

Cecily, now 3 months old, was dressed as Captain Marvel for her first Halloween "because she’s a real life, true superhero," Murin said, noting that Cecily had the procedure done "to repair a rather large hole that she was born with."

"A lot of babies are born with this condition, but the majority of them close up on their own," she continued. "We found out about this when I was 22 weeks pregnant, so we'd known for a while that this was inevitable."

"But no matter how much you prepare mentally, watching your impossibly tiny new daughter go through an incredibly serious and invasive surgery is gut wrenching at best," Murin added.

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As she continued with her post, Murin said that she found inspiration after her daughter's surgery while she recuperated. "Helping her recover day by day, breath by breath, has been humbling and inspiring," she said.

"Our daughter isn’t even 4 months old and she’s already more badass than I’ll ever be," the Broadway star added.

Murin and her husband of five years, Colin Donnell, welcomed their first child earlier this year in July.

"We are absolutely head over heels in love with Cecily, and parenthood is already the most insane and beautiful thing in existence," the couple previously told PEOPLE. "Now please excuse us as we drop off the face of the planet for a little while to keep this little peanut happy and healthy, cause she's gonna change the world."

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In her social media post, Murin added that the entire ordeal for her and Donnell was "made slightly less difficult" thanks in part to the staff at Mount Sinai Kravis Children's Hospital in New York.

"I have never felt so supported and taken care of, and I was able to sleep at night knowing that she was in the very best hands there are," Murin said. "There is no way to adequately thank the people who have quite literally saved your child’s life, but we won’t stop trying."

Murin then gave an update on her daughter's health, where she wrote that Cecily "is doing so, so well now," adding, "She’s the most heroic person I know, and I can’t wait to tell her stories about how brave she was when she was just a teeny bean."