Lime- Don't use anything for bias tape that wasn't cut on the bias. The reason the stuff is so useful is because it can stretch slightly and go around curves (like the bottom of a skirt) with ease (and an iron). If you, understandably, don't want to use the cotton bias tape from JoAnns, you can make your own using fabric you like. It'll take around two yards of fabric to cut one strip of bias tape, but only a few inches beyond that for every subsequent strip. There are bias tape makers that will iron the strips for you, or some tools to fold them correctly so you can hit them with an iron, or you can just measure and fold them yourself.
But grosgrain ribbon won't take curves easily, or really at all.
Alternatively, to hem the skirt, you can try slightly gathering the edge you're folding under. That may make it take the hem a little easier. It's not a great option if you don't have time, but I often prefer hemming things by hand, because it doesn't end up as wavy. (But then I would do everything by hand if I could, most of the time.)
Clothes make the man.
Naked people have little or no influence in society.