Ok, this is hard.
Direct Answer: No, I wouldn't. I think there are more important issues in relationships than plain attractiveness. In general, I wouldn't... get "intimate" with a woman unless I have spent a hell of a lot of time with her before (1+ year).
In fact, the important thing is that you have a psychological bond between you: you need her and she needs you. Together you are one. If she just asks you, without you feeling a non-sexual affection for her (the psychological NEED to take care of her, to comfort her, to be with her and so on), then, by all means, don't do it. You would end up going hunting with your father... you being the game.
Otherwise, if she really were special to you (and as long as there's no blood connection), feel free to do anything you like.