On the 1930 census, Bonnie claimed to be 31 years old, and thus presented herself as born in 1899-1900.
One caveat is that, at times, census enumerators would call at a home and not everyone (or even no one) would be present. Rather than make a “return visit,” the enumerator might have asked the person who was home (or a neighbor) the name and age of the other, not-at-home, residents.
Not that the analysis is incorrect, just that we are always uncertain as to who supplied the information to an enumerator.