"I have waited and dreamed of you my whole life. You are more than I could have ever imagined," the new mom began her sweet note

Rumer Willis is celebrating Mother's Day for the first time.

In an Instagram post on Sunday, the Once Upon a Time ... in Hollywood actress, 34, shared photos from daughter Louetta Isley's birth.

Penning a letter to her little girl, the new mom wrote, "I have waited and dreamed of you my whole life. You are more than I could have ever imagined."

"You have changed my life in the most profound way. It is the privilege and honor of my life to be your Mother and I will do everything and anything for you always. I hope you never stop wanting to sleep next to me or take baths with me," she continued.

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Related:Rumer Willis Bares Her Bump in Exclusive Photos and Reveals What She'll Miss Most About Pregnancy

"I can't wait to see who you are, although I feel like I have known you my whole life. One of the first things I said after you were born was 'oh my girl, I missed you,' " she continued. "I didn't even realize I had said it til @buuski told me later but it's true. I feel like i have always known you and you me. You are the most beautiful creature I have ever met. I still wake up every morning and can't believe you are mine."

"Thank you for choosing me to be your mama, thank you for trusting me to guide you through your life. Every moment and contraction and every bit of the pain of birth was worth it and I would do it a thousand times over if it means getting to spend one sec with you."

Addressing boyfriend Derek Richard Thomas as her "partner in crime in this uncharted journey into parenthood," she went on to say, "Thank you for giving me the gift of this beautiful soul and for catching our girl as she came into the world and for holding such beautiful space for me as I brought her into the world."

"She is so lucky to have you as her papa and loves you so much. We are so grateful for you and love you so much."

Rumer then shared a message for sisters Tallulah Willis, 29, and Scout Willis, 31, who can also be seen in photos from the birth.

"To have you there to share in the moment that I was able to bring my girl in the world is a moment I will never forget," she wrote. "You have watched and supported me on the journey and know what it meant to bring another precious girl into our lineage."

Concluding her message to Louetta, she wrote, "I love you my girl you are the greatest joy and gift of my life. Love your mama."

Speaking with PEOPLE ahead of Louetta's birth last month, Rumer shared that she is thrilled to kick off the family's next generation.

"[My parents] are so excited. My sisters are so excited, and it's so fun to be bringing in the first grandkid in our family, especially because we're such a huge group at this point," she said.

The actress also noted at the time that her first pregnancy had been "humbling."

"I have so much reverence and respect for women now. I feel I've had an easier time physically than most of my friends," she added.

"Also, because I'm so excited, even those moments that are challenging, or feel frustrating, I'm just so excited, that always kind of trumps [everything]... But, it's wild. It's the wildest experience, even more so than I ever thought of."

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