There are three ways to inflect feminine nouns in Norwegian:
a woman - the woman - women - the women
All feminine (indefinite feminine, definite feminine)
ei kvinne - kvinna - kvinner - kvinnene
All masculine (indefinite masculine, definite masculine)
en kvinne - kvinnen - kvinner - kvinnene
Mixed (indefinite masculine, definite feminine)
en kvinne - kvinna - kvinner - kvinnene
The mixed form is suprisingly common, and is taught for many feminine nouns in this course. However, your indefinite feminine, definite masculine is incorrect.
I think that it would be better if you start saying ei kvinne and kvinna from the beginning
It would definitely be easier but you would also risk confusion when encountering en kvinne and kvinnen for the first time while on a holiday in Norway.
Therefore, both forms are presented to you so your mind can register it in everyday speech regardless which form you eventually end up choosing for yourself.