"My grandma is seventy-five years old."
Translation:He kanahikukūmālima makahiki o koʻu tūtū.
Yeah, me too. I think culturally, Tūtū is the name most often given to grandmothers, and is not often used when referring to grandfathers. So DL, and the general community, think of tūtū as grandmother when used by itself without the gender spec.
"Ahwen visit my tūtū" strongly implies "I just spent some time with my grandmother."
Among native speakers, tūtū is also common for "grandpa." Niʻihau speakers use tūtū for either gender, and only add wahine or kāne if there may be some confusion about which is being referred to. If the name is provided, as would be common in general conversation, no need for gender reference.
Excellent point (the extra ma). The DL spelling gives no reply in wehewehe or manomano. In fact the spelling you give here does not work either. It does come up as the correct answer in google translate though. Does this mean that all the spellings used in DL are wrong? Mahalo e rabelon.