When I drove to Pittsburgh about a year ago, there was a girl in Lancaster (which isn't too far from you) called Katie Butterfly. (I think thats what she calls herself.)

I didn't end up meeting her as our scheds didn't match up but I remember her having v.good reviews, slender and right around the upper part of the age range you are looking for, maybe a tad over.

I've met Katie. Had an absolute blast with her!