"It's so weird, 'cause when you're little, you're like, 'That age just feels aggressive,' " Alba told host Jimmy Fallon. "You're just like, 'That's a grown-ass person.' "
"And when you're here, you're like, 'I guess this is what it is,' " she added. "You know you have so much more life out there to live. I feel like everything is just sort of connecting in a really cool way."
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Last month, Alba shared a video that captured her intimate birthday festivities. In the clip, she celebrated with an outdoor bash seemingly thrown at the Honest Company offices, complete with a bevy of pink-and-gold decorations, a full food spread, birthday hats and delicious cupcakes.
The Tonight Show Starring Jimmy Fallon
She also marked the memorable occasion with a smiley snap on Instagram featuring her family: husband Cash Warren and their kids (daughters Haven Garner, 9½, and Honor Marie, 12, plus son Hayes Alba, 3), dressed up and seated together in front of a balloon wall.
"My heart is full of hope and everything I do in life is for you," the L.A.'s Finest alum captioned her sweet post.
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Alba is also celebrating Honest going public on the Nasdaq, having told PEOPLE this week that it feels "humbling" to now lead a publicly traded company as a Mexican-American woman and mom.
"You can be all of those things," she said. But the mogul believes there is still additional work to be done to successfully funnel more women into "leadership roles across the board."
Later in her interview with Fallon, 46, the Dark Angel alum said that going public feels "wild" and like "a dream come true."
Of whether she got emotional while ringing the bell, Alba said, "I was trying to keep it together, but ... it was one of the most amazing experiences, especially to have my family with me and my team. It was incredible."