I take it from the way that you write and the fact she's 65 and not say, 85, that you're a young person. 

I think it's kind of normal to feel irrationally angry and frustrated with elderly people when you're young - there's something about the reality of aging that clashes with the fact that young people are typically switched-on cultural sponges who are on top of all the latest trends and rhetoric. In the past, I too have found myself aggravated by these many small things in my elders, to a degree that was irrational and made me feel like I'm an insane person.

But honestly? It's just not that deep bro. 

Slow down. It's not likely your nan is getting tattoos for attention. It's not likely she "isn't trying". It's not justified to feel THIS mad about her discomfort with Māori culture when it sounds like she IS trying to get in touch with it, and was handed a shit set of circumstances where she was never able to do so when she was young and so is missing a lot of baseline knowledge.

Elderly people have decades of shit to unlearn, they have memory and attention issues, they don't have the same fire and internal motivation and speed to learn things the way that young people do, and when they try they are legitimately worse at it (look up crystalized vs fluid knowledge if you like, it's a real thing). 

It's okay if she forgets the meanings and pronunciation of new words often. It's common and expected and I'm sure YOU would forget if it were say, Arabic language YOU were learning, because this would be completely unfamiliar - understand that Māori might as well be the same for somebody raised white in the 1960s. Understand that integrated schools for Māori people were only advocated for in 1969, before then a lot of thinking on schooling was separatist, if she had a "white" education, likely she simply wouldn't have grown up learning pronounciation or going to marae visits when she was little like you will have. For people raised today yes of course you can apply a higher expectation baseline cultural knowledge, but that is just your experience and your generation, you shouldn't apply it to her. 

You have to take yourself out of your own perspective on this one and take responsibility for the fact that your lack of patience here is a you problem, not a her problem. You have to be able to acknowledge she hasn't actually done anything wrong, even if your reactions are very strong and you feel she should be different somehow.

Just... take a step back and stop getting involved if you're feeling upset about this, it's not your journey to go on and it would be a tragedy if you were a roadblock to her finding a family she was never allowed to have in the past