The Kill Bill star, 42, and her partner Arpad Busson became parents to Rosalind, known to family and friends as Luna, on 15 July (12).
The tot is a half-sibling to Thurman's two children Maya, 14, and Levon, 10, with her ex-husband Ethan Hawke - and the actress is convinced she's a more relaxed mother now she has experience on her side.
She tells Gotham magazine, "When I was younger and became a mother, I didn't think I could do anything else; I was completely overwhelmed.
"I felt guilty and afraid about working, guilty and afraid about not working. It's very overwhelming for a younger person, which is why it's awesome to get to have another baby when you're grown up."
Opening up about how she juggles her responsibilities, Thurman adds, "The question of balance has always been kind of a funny one to me because I don't think there is any balance. I feel like I've never done enough. I do think I'm pretty good at home, but trying to balance my energies outside the home? It's a challenge; there's so much more I want to do and can do."