Translation:The girl with green eyes is my cousin.
No, that is the point of this lesson. Unfortunately we still do not have the Tips and Notes.
The rule is: "Paired organs of the human body (ruce, nohy, oči, uši, ramena, kolena) use even the so-called dual declension in the plural (you can find more about the declension of body parts here). " from https://mluvtecesky.net/en/grammar/cases
So you have očima as the correct form, but you have s námi for other plurals.