Yes, those are an OK size. For your future education, a BP has this (pics of my own boy):
Notice that slit-looking piece? Skin is folded up into the snake's jaw at that point, since their bottom jaw is split into two pieces unlike a human's. So, their entire process is three part, compared to a human's two part. This allows them to eat things larger than their head with ease, and thinking a snake can only accommodate something that matches their head size can lead to underfeeding (such as feeding rat pinks to an adult BP).
This thus unfolds like so (again, pics of my boy, thankful he's so good about photographing):
Obviously, you shouldn't just feed them WHATEVER size, but they can certainly (and should certainly) be eating things wider than their head. Some struggling is only natural also, to alleviate concerns: snake dinner is like a human trying to eat a pie with their arms tied behind their back. Not exactly graceful.