Though I am girl, I going to give my opinion. It's fine, but like the guys said it's kind of boring. Maybe wear a white tank top, blouse, and etc... That looks great on your figure and that can be tucked into the skirt. Also maybe add a necklace, belt, and high heels. Knee length skirts can be super attractive on girls but it all depends what you wear with it. Oh, when I mention the white tank top, blouse, & etc..., it all depends on what color the skirt is. Like if it is dark blue skirt, I find it that, it looks good with white.
I think that one is fine. There is something about what the girl wears that makes her unattractive... maybe it's the socks. But the skirt itself is okay. I wouldn't prefer any other length. shorter skirts make it seem like your @$$ is hanging out and longer ones are somewhat dorky sometimes (unless you compliment them with other appropriate clothing).