"I feel good and, thankfully, from my husband and my family and friends surrounding me, I feel beautiful," she tells PEOPLE
Nick Lachey Vanessa Lachey Welcome Daughter

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Vanessa Lachey has already bounced back after giving birth to her baby girl in January.

But exactly how much she’s shed since becoming a mom of two is still a mystery — even to Lachey.

“I don’t even know my size right now, honestly,” she tells PEOPLE while promoting her partnership with March of Dimes. “I did the fitting for [this interview] and I was like, ‘Just have everything from [size] 4 to 10.’ I really don’t know!”

Her ability to focus on her family of four — including son Camden John, 2 — can be credited to Lachey’s amazing support system, starting with husband Nick.

“It’s more about the perspective that I have as a woman and a mother and a wife and how I feel it’s not about, ‘Gosh, I need to get back to a certain size’ or ‘I need to be a certain way,’ ” she explains. “I feel good and, thankfully, from my husband and my family and friends surrounding me, I feel beautiful.”

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The actress is hoping her stance on postpartum weight loss will cause a rippling effect in other new mamas, shifting the conversation from getting in shape to embracing the experience.

“Ladies, you are a beautiful woman, you are a beautiful being, you just birthed a human being — let it be,” she says. “Don’t let that beat you down. Just feel good about what you’ve done and what you’ve accomplished and feel beautiful in how you are.”

Lachey adds, “Your body’s going to be the way your body’s going to be. I think if we all just have a positive outlook and take care of ourselves in that way, it will be a great outcome because we’ll love ourselves.”

And while her daughter is still years away from adulthood, Lachey is looking forward to “what’s to come” with 3-month-old Brooklyn Elisabeth.

“I’m so excited [for] the woman that she’s going to be and the mother that she’s going to be and the person she’s going to be,” she shares.

It seems as though the couple’s son Camden, however, has already chosen his path in life — right behind his famous father.

“Not only does [Camden] have the singing ability and love the music, but he also has Nick’s terrible dancing ability,” Lachey, who recently filmed a TV pilot called Not Safe For Work, jokes.

“There was actually a moment when Nick was doing some 1996 98 Degrees move in our bedroom … and Camden was right next to him mimicking him. I went, ‘Oh no, oh no, here it comes, you’re the mini version of that.’ But that has done well for Nick so maybe that will do well for Camden!”

— Anya Leon