Well, I can remember Yutaka's name, but only because he keeps being called a yukata instead. And I can remember Tane, because it really is an odd and cute name. But... don't ask me what the older brother's name is. ~w~
As for age, I sort of assumed they were roughly the same age, but I'd be hard pressed to tell you why. I want to say the plot felt like it was headed that way...? Maybe, because it feels like the goal of this is to have (or at least start with) a low-key comfy relationship, and and age-gap wouldn't be in service of that feeling of mutual safety and comfort. Or maybe that's too much of a stretch.