Well you know what they say about women with big feet don't you? Wait, no, that's men, hopefully the same doesn't hold true for you=P. I've never seen a woman with feet so big it drew my attention away from the rest of her; I'm sure you're fine dear.
I wouldn't say hate it, but I had to answer this question it is something that seems to bother me out of nowhere a lot lately. I started noticing the feet of some women that I see on regular basis looking rather large for their bodies. It could just be that most of them are not that tall and so it makes their feet look bigger in proportion to their small stature, I don't know. A girls feet have to look better than mine, if they don't something is wrong. To answer the question, size doesn't matter too much, as long as they aren't so big she looks like she is wearing clown shoes, then I'm OK. I wear a 10 1/2 to a 11 so I don't want her feet to look way bigger than that.
I like pretty feet on a girl and to be honest I usually consider smaller feet like a size 5-7 to be cuter on them, but there is nothing necessarily wrong with larger feet as long as they are still cute and maintained.