As most have already commented, runs small in upper body. i'm always a 2 or 4 petite (5'1", 120# max, 36aa, athletic build). the petite s was exceptionally small in upper body and no chance of it stretching enough to be comfortable. since i read other reviews before purchasing i also ordered the petite m. pm was too big under arms. i exchanged both and purchased a regular s in store. fits great, though would have liked it a mere 1" shorter.
the sizing should have been 2,4, 6 etc.
i'm keeping the