EXCLUSIVE: Chrissy Teigen Gushes About Daughter Luna: 'There Is No Feeling Like That First Smile'

Chrissy Teigen opens up about her post-baby diet ... or rather, her lack of one.

Chrissy Teigen couldn't be happier about her new life as a mom.

The 30-year-old supermodel gave birth to her daughter, Luna, last month, and opened up about her first child with husband John Legend to ET on Tuesday.

"We're so happy," Teigen gushed exclusively to ET's Jennifer Peros. "It's been really exciting and fun, and every day is so different, and seeing all her little changes is so cute."

WATCH: Kelly Clarkson Jokes She's 'Jealous Like Jonas' of Chrissy Teigen's Amazing Post-Baby Body

"Her eyes have uncrossed a little bit, and, like, now, rather than looking right through you, she looks at you, which is really nice," she joked. "But it's the little smiles that get you. ... There is no feeling like that first little smile, your first Mother's Day, which was so beautiful and sweet to me. The entire day my eyes were on the verge of tears because I was so happy."

Of course, the always candid Teigen is open about her struggles as well -- particularly, breastfeeding.

"The feeding schedule surprised me a lot," she admitted. "If you kind of do the math, you're kind of breastfeeding for 10 hours a day total."

"It's very loving and sweet, but it's not easy," she added. "It's hard to work your entire day around getting her the nourishment she needs because they are just little animals."

Though, despite having a lot on her plate, Teigen is still finding time to indulge in her passion -- cooking. She recently partnered up with Lawry's Seasoned Salt partly because of how much she naturally uses the spice, such as in her delicious recipes in her cookbook, Cravings.

"I jumped right back in the kitchen because it became my spot where it was nice to be up and moving," Teigen explained. "When [Luna] was down at whatever time, it was nice to be able to stand up and be in the kitchen with John, and watching TV and enjoying ourselves."

And despite Teigen causing plenty of Internet chatter last week thanks to an Instagram pic of her in a crop top and tiny denim shorts flashing her enviably slim physique less than a month after giving birth, she insisted that she still has some baby weight to lose.

"Oh gosh, I do," she laughed. "I'm only four weeks out from birth, so I still have a couple more weeks before I can work out -- which is fine with me. I love the feeling of working out, but I've never been a gym rat, ever, so now, it's all about taking in what I can if it's good for the baby, because it all translates to her in a way."

Surprisingly, she said she hasn't changed her diet much.

"You just don't think about food as much," Teigen explained. "So it's not that you're not hungry, or that you want to diet -- food just doesn't cross your mind. It's like whereas before it was number one on my list, now Luna's up there, and John and keeping the dogs happy, because they get jealous. And then you're like, 'Oh, I haven't eaten in seven hours, this is horrible.'"

As for all the mom-shaming she's been dealing with -- which had her husband sweetly coming to her defense last week -- Teigen said she now tries to not to pay attention to the haters.

"It does seem all silly now," she stressed. "Like, anything that you got frustrated over about before, nothing really matters anymore. And I think you just let things go a little more."

"It is hard when it turns to ... people are grading you on your personal decisions," she admitted. "You just realize you'll never make everyone happy. ... I'm learning to let things roll off my back a bit easier. I have more important things going on now."

WATCH: Chrissy Teigen Cheekily Responds to Twitter Backlash After Going on First Post-Baby Date With John Legend

Last week, Teigen proved she's a multitasker when she was spotted breastfeeding her newborn daughter while getting glammed up for a photo shoot in a Snapchat video. Watch below: