I agree it's all about the size of the snake & they can be hard to measure (or weigh, if you don't have a good gram scale), so I also judge their prey size by the
size of their unfed mid-body, feeding prey that is slightly narrower than the snake. Keep in mind that slight underfeeding is healthier for them than slight over-
feeding, & also that many snakes being fed on the large side are more likely to be picky eaters & want to skip some meals, which tends to frustrate & annoy most
keepers.
Feeding every 10 days sounds pretty reasonable to me, but as previously mentioned, many snakes stay in "feed mode" for hours or few days, especially in warm
weather; also, that young adult female BPs tend to have more appetite than male BPs, instinctivly to size up for breeding, so if this continues you might want to
feed meals slightly closer together, or slightly larger in size. But it's certainly not an "emergency", & whatever you do, don't give in & feed another prey item on
top of a meal that's partly digested...unless you want to see your snake regurgitate & waste both items & then have to with-hold food for a few weeks while they
replenish their digestive enzymes adequately (so that another regurge doesn't occur).
Short answer: don't worry about it![]()