Understanding この年にして in this sentence Grandad has just promised something he is unlikely to be able to fulfil. He then thinks to himself: > **** > If push came to shove and I were to do something like run away, I would be a liar and a traitor. I shouldn't go as far as to say that I don't know what will happen. I translated as 'at this age', but I don't see the relevance. If he fails to fulfil his promise he'll be a liar and traitor whatever his age. What have I misunderstood? The second sentence also seems unconnected. I must be missing something here.

> {}{} "at this age"

The nuance of the phrase in the context is that the speaker would not like to be a liar and traitor at his old age. That is to say he does not want to be like that at the last stage of his life.

Regarding your TL of the second sentence, you missed the structure around the middle part of it -- .

There is no equivalent of "go as far as to say **_that_** " in the original. There is only " ** _even_** talk about (the things you don't know)".

It looks as though you mistook the for the quotative . That would make a huge difference:

> "I shouldn't be even talking about the things I don't know would (actually) happen." .