Why does Ezinma call her mother by her given name?

She does not know how to show proper respect for her elders.

It makes her feel more grown up.

She wants to be different from her peers.

It is a way of showing that they are equals.

Ezinma calls her mother by her given name, Ekwefi, because it is a way of showing that they are equals. Ezinma and her mother Ekwefi are very close, having bonded over having little secrets such as eating eggs when it was forbidden. She feels she has become equal to her mother, and doesn't have to refer to her as Mother anymore, but can use her real name.