My 8 year old DTD's have this also. They are both quite dark skinned and of mixed race with dark hair on their legs (and also back and arms, but they don't seem to notice this).
One has been upset by it due to having been teased a bit at school.
The other is not bothered by it at all.
I told my upset DTD that I think she is still beautiful, most of us have hair on our legs and due to the colour of her skin I felt that the hair wasn't too noticeable.
I then asked her how she felt about it. She said she didn't mind it herself, but just felt embarrassed and upset if others mentioned it. We then had a little chat about responses she could give if teased again and she has been fine about it ever since.
I have also told both of them that at any time, if they themselves start to feel uncomfortable about the hair, there are many things we can do to sort it (I mentioned special creams, lightening etc).
I would personally go down the lightening route with mine first, as the hair is quite fine but dark and their skin is quite robust.