It would raise eyebrows here in the uk as there is a noticeble difference in the age.
Would it ?
Maybe a little, but not considering she is 27. If she was 17 and you were 31, then you might have a point. As it is, she is old enough to know what she wants.
As long as she is financially independent and not after any cash you might have, then I say relax and enjoy it.
If your only issue is the age-gap, then I say that there is no issue. If you think things are going too fast generally, then that's a whole different thing.