Im curious why "my" needs to be inclded in the translation.
Because shi- means "my".
For "a" grandmother, you would use "amásání", for "your" grandmother, "nimásání".
You can find all this in the small grammar sketch I wrote about pronouns, nouns and postpositions.
Judorange, could you please tell me where I can find your grammar sketch? Ahéheeʼ
Here you are: https://forum.duolingo.com/comment/29424104
When I have time, I should start tackling verbs!
The correct answer includes "grandma" but rejects "grandmother."
Dude. Grandmother should be acceptable
Normally yes, but Duolingo has to check that you understand what exactly it means.