My 2 cents: No, not overweight. And that little bulge just above where the vent (cloaca) would be looks like she's going to take a dump pretty soon, so put on your best dry clean shirt or let her get some exercise on your best upholstered furniture- NOT!From where I sit, she's somewhere between slim & ideal on the above chart. BPs are not supposed to be built like colubrids.
Also, many female snakes have "hips"- at least they give that (slight) appearance because their tail is shorter & tapers more abruptly from the cloaca than the longer tails of male snakes. Exactly which is the case with this snake (or maybe both?) is very hard to discern from just a photo.