'I couldn’t be more proud': Karlie Kloss says she's thankful for becoming a mother as she celebrates son Levi's third birthday

LOS ANGELES, CALIFORNIA: Karlie Kloss is celebrating her son's third birthday. The supermodel shared a series of photos on Instagram on Monday, March 11, in honor of her son Levi's third birthday. The former Victoria's Secret Angel included adorable photos of her son holding birthday balloons, reading books, enjoying the outdoors, and spending time at Coney Island.

"3yrs ago today, you forever changed my life and I couldn’t be more proud and humbled to be your mom," Kloss wrote in her caption, according to People. "Thank you for making me a mommy. happy birthday Levi, thank you for choosing me and @joshuakushner. We couldn’t love you more.✨🤍🎂✨," she added.

The 31-year-old shares sons Levi, 3, and Elijah, eight months, with husband Joshua Kushner, 38, the son of real estate developer Charles Kushner.

Karlie Kloss say she could not control her posture during her pregnancy with Elijah

Kloss said that one thing that she could not control during her pregnancy with Elijah was her posture.

"Just being pregnant for nine months, I found my posture got so bad," she shared, adding "So now I'm relearning my whole anatomy and trying to fix it, straighten my back." She also revealed that her fitness routine has also changed with her becoming a mother.

"My routine has evolved. It's gotten more efficient. I feel like my philosophy has gotten much more about strength in sustainable ways. So I do light weights and also body weight exercises. I travel a lot still, so I don't always have a gym nearby," Kloss explained.

"So I like to do things that I can do anywhere. And I like to squeeze in the workout first thing in the morning. Actually, the first thing I do in the morning is check my sleep data," she continued, adding "I'm weirdly competitive with myself over my sleep."

Karlie Kloss opened up on how pregnancies had resulted in a greater love for herself

The former Victoria's Secrets lingerie model previously told the outlet about how her pregnancies had resulted in a greater love for herself. "I had a conversation with myself a while ago because I want to be in shape, but I also have more self-compassion because my body created life," she said.

 While marking her son's birth on Instagram in August, Karlie echoed the same sentiments. She wrote next to a photo with her sons, "Going into 31 with a heart full of gratitude 🙏💛✨."