5'2" w/ a 50cm sounds about right, unless you have disproportionately stumpy legs. When I stand over my bike (which is a tad on the big side for me) it bunches up the crotch of my pants a little. as long as you can stand over it with your feet flat on the ground, I wouldn't trip. Why don't you ride a different sized bike at your LBS to feel what is good for you?