Ah ok allright you actually have a point there.. It was just a quick reply I typed up there, but guess I was thinking more along the lines of the times you see Harry's parents as ghosts or in the mirror of Erised. But guess I didn't think too clearly now, because their ghosts wouldn't age actually. Hm.
Oh and by the way I didn't really have a clue how old Harrys parents were when they died. I thought they would have been older, because the ages they were meant to be when they died seems a bit young to me to be having a son of a year old. But maybe that's just me.

Anyway, you're absolutely right then. They are not so well casted then, maybe because the general public would have trouble seeing them as Harrys parents if they would have been portayed by younger actors?