I know a lot of puppies' ears take a while to drop. Jimmy's ears appeared high for ages, though I can't remember exactly when they "dropped", definitely later than six months though. His ears still look high a lot of the time, it's just the way he carries them...... he's particularly fond of raising them when I try to take a photo.
Must be the alert thing that Linda mentions.
I don't know if it's my imagination, but it always appears to me that blue roans generally seem to have a low set ear carriage whereas reds/golds are often quite high.