This sweater is so cute! I'm 5 ft., around 128 lbs and ordered a small, which fits nicely and doesn't pull at the buttons. One observation I can offer is that the collar seems a bit high for a 'summer' sweater; it's not problematic but just an unexpected choice made in the fabrication of the sweater.
As for the yoke, the little crab pattern is GREAT! I'll get good use out of this piece.