My daughter is 11. She is careless with wiping and often resists showers.
Looking back, I don't remember paying any attention to it at that age. I do remember have quite oily hair that my mom askied her hair care friends how to deal with. I think part of it was that I had not yet learned how to wash my long, thick hair properly. Recently my daughter and I were showering together after swim practice and I realized that she did not know how to wash HER hair.
I don't remember at what age I stopped bathing her and expected her to know how to take care of herself from then on, but the above experience has made me wonder what else I just assumed she knows how to do.
In an effort to help my daughter learn that it is her responsibility to remember and do hygiene tasks, I have mostly stopped telling her to do " them, but say things like: "After you've brushed your teeth, ..." or "if you've already brushed your teeth, you can watch TV." Occasionally we do have to say, "You stink, go shower." ... but other times we try to have frank discussions and point out to her that most people are too polite to tell her that and often will just avoid her instead-- and that we tell her because we love her and would rather that she hear it from us.
I would keep encouraging and teaching your daughter, but not make it a big deal. I think it is more normal than many people might think.