Blake Lively says she has "always felt like a mama" – and now that she actually is one, the role feels natural.
"I don't feel like it's a massive change," she tells PEOPLE exclusively in this week's cover story.
The new mom and Preserve founder, 27, who welcomed her first child with husband Ryan Reynolds in December, is the youngest of five kids in a blended family and wants a big brood of her own.
"I do want to just enjoy this moment," she says. "But I also feel like my first child is going to be the oldest sibling to the next kid, and that may change with each and every year.
"I'm looking forward to how one baby influences the other, and to my family as a whole, to every single chapter."
Just named to Forbes's 30 Under 30 list of influential Millennials, she is also looking ahead to expanding Preserve, the lifestyle site she launched in July featuring a mix of fashion, food, beauty and philanthropy.
"So much of the inspiration came from my mom and my dad and my siblings," says the actress, who next stars in the period drama The Age of Adaline. "All the things I feel like I'm good at are thanks to my family, and they're things we're now embracing at Preserve: cooking, decorating, artistry. Family is at the heart of everything I do."
Between marriage, motherhood and her blossoming business, "This is the happiest time in my life, and I could say that every day," she says. "I often feel like, 'I can't believe I'm experiencing this.'"
Reporting by KATE COYNE
For much more from Blake Lively, including her best tips from Preserve and the secrets of her maternity style, pick up this week's issue of PEOPLE, on newsstands Friday