Kamala Harris' parents were both part of the Afro American Association in the early '60s which literally created Kwanzaa and established the Black Panther Party -- so, yeah, seems likely that she would have celebrated it as a child.
Kamala once again claims that she celebrated kwanzaa as a child
Kamala Harris was born in 1964
Kwanzaa was created in 1966 and didn't really take hold until the late 70s and early 80s