Love works in a mysterious way that none of us really has an
answer to how it works.
So, we can't really give you a reason about why you fall for her.
But I do know that love doesn't need to be all about looks.
Sometimes the person you fall for is a total opposite of your
idealistic dream person. But what's wrong with that? There has to
be something special about her that causes you to like her, to miss
her like you do now 
So just enjoy the feeling, go after her if you wish to be with her,
and stop questioning so much about how love works.
As my siggy says,"Love is not a
because, it is a no matter what"