Meh. It's not got sufficient history as a boys' name (not in Scotland, anyway, where it has none) to feel totally out of synch on a female. But it's so cutesy. I have a hard time picturing an adult, of either sex, called
Colby.
Colby Scarlett gmv, followed by
Colby Alyssa. I dislike
Colby Anne - the style of
Anne is just too different and the names seem silly side by side.