"That surprised me – how much I loved [nursing] and how effortless it has been to pump anywhere in the world," she tells InStyle for its May issue.
Garner, who turns 35 Tuesday, says that life her with 16-month-old daughter Violet has been a real joy. "I don't want to miss a second with Violet," says Garner, who feels "intoxicated" when she's with her daughter.
Garner says when she's away from her daughter, she feels like a "love-struck teenager."
And Violet feels the same way – especially about her father, Ben Affleck. "Violet prefers him to anyone," Garner tells the magazine. "He's a teddy bear of a guy. Nothing makes me happier than to see the two of them together and her little hands on his face."
In fact, Affleck is a dream come true for Garner. "You know how as a kid you picture yourself with a tall, handsome husband, and you imagine him cuddling your baby?" she asks. "Ben is like that, like, on crack."
Even pal – and neighbor – Reese Witherspoon raves about their family life. "She's a doll," Witherspoon tells InStyle. "We talk about mom stuff... Jen loves celebrating the traditions of home and family."
Though her domestic routine keeps her busy, Garner already has another film in the works; The Kingdom, costarring Jamie Foxx and Chris Cooper, will be released in September. In the movie, Garner plays an FBI agent. She's also enrolled in an online political science class, saying, "It was a New Year's resolution to start doing something for my brain."
But Garner's biggest task has been to shed her baby weight. "You're supposed to look a certain way when you're a celebrity, but I want to take care of my baby, and those two things don't mesh very well," she says in the interview.
Plus, it can't hurt that she's soon due to shoot a film in which she plays a yoga instructor. "Pretty soon, like it or lump it, I'm going to have to do some downward dog poses," she says.
And while more children are probably on the horizon, Garner tells the magazine, "I need to work this year," but notes that she's achieved a balance that makes her happy. Garner says: "I feel filled up at the end of every day."