Barrymore, 40, said one of the most important and challenging things about being a mother is watching out for her daughters' safety, reported People magazine.
"I think as a parent sometimes I feel very overwhelmed with all that there is," she said on the sidelines of Safe Kids Day.
Even with all of the worries, Barrymore is loving being a mother to two adorable little girls.
"Two is even better than one. I can't believe it," she said.
When asked how Olive is handling her big sister duties, Barrymore said, "She's great. She's awesome.