If
@LustyHeart or anyone is still wondering.
Its because she refer herself as 'warawa', a prideful version of 'watashi'. Usually used by those with standings of a noble to deities.
The translation doesn't use the distinction for it, only 'I' and 'Me'. Thus it become confusing.
In this matter, she is actually being made fun of, because nobody else but protag knows she was Maou.