meh, as long as she doesn't go in for surgery for cat ears or some shit you are probably okay (especially if you didn't notice till now). let her wear the cat ears to bed but tell her you won't wear a cat suit.
if it becomes a serious barrier to the relationship, then worry about it, but for now it sounds like a mild fetish (that you could secretly enjoy in appropriate doses)
if it becomes a serious barrier to the relationship, then worry about it, but for now it sounds like a mild fetish (that you could secretly enjoy in appropriate doses)