>That is, if I fail it, it's not because I am older, it's because I don't know stuff fresh grads know.
I believe this is exactly the point that the parent poster is making. You don't know the stuff fresh grads know because you're older (obviously this isn't an absolute, but likely). Therefor, structuring the interview around stuff that only fresh graduates are likely to be up-to-date with would be discriminating against older people.
If you fail, it is at least related to you being older, if the focus of the interview was designed around hiring fresh graduates.
I believe this is exactly the point that the parent poster is making. You don't know the stuff fresh grads know because you're older (obviously this isn't an absolute, but likely). Therefor, structuring the interview around stuff that only fresh graduates are likely to be up-to-date with would be discriminating against older people.
If you fail, it is at least related to you being older, if the focus of the interview was designed around hiring fresh graduates.