I think the hairstyle, headband, top, and the shorts ALL look VERY "1950's-Like" to me...what kills the shot is the location she's in. The seated pose, with her feet curled to the back side, arms up, big smile, ALL of that looks very pin-up-ish...if she were seated in an indoor environment this would be a winner! But that tiny rivulet of water, and the bush behind her are just killing it...
Now, if she were perched that same,exact way on say a big ROCK at an actual river or lake...that would be good!!!