Gorgeous BP! Your snake clearly isn’t underweight nor are you underfeeding it. Your BP will reach it’s optimal health and size in due time on any reasonable feeding schedule. If you’re feeding every 7 days your critter might grow a little faster than if you feed it every 10-14 days but either way is fine. I never weigh my snakes or their prey. I just don’t see how it relates to the health of the animal. If anything it seems to cause more worry and confusion rather than providing actual beneficial information. Snakes are pretty simple creatures. If they have adequate heat, hides, food and water they’re usually just fine. If your snake is eating, pooping, and shedding consistently without issues then there’s usually no cause for concern.