Washing oily hair often actually makes it produce more oil. I washed my fine, blinde, oily hair twice a day as a teen because that was how I was taught to deal with it. I learned much later that both washing and brushing too much exacerbates the problem. I love having long hair, but up-dos and braids let me skip a day between washings. I also never blow dry.
My daughters have similar hair, and I am training their hair to not use shampoo, but do cleansing conditioner washes every other day instead. It never looks dirty or smells oily. One of my girls likes hers kept in a pixie cut, which is great because it is so thin.
Jill's hair actually looks pretty good in a side braid. It is very thick, even at the bottom. I've noticed many of my high school students have the over long unbrushed hair look, too. I feel very old with my coiffed hair, but when I was a kid I hated it when people said my hair looked stringy, and that is all I see with that style.