I won't say wrong if he’s healthy, but in my opinion, its not enough food.
I fed my hatchlings big fuzzy mice 10 days out of their eggs.
I feed every five days, so the next meal was hopper mice(now 15 days old).
The third meal was a rat fuzzy(bigger than hopper mice)
and so on....
These snakes are all about 12-15 inches long now(never measured them).
The food items leave a slight lump in the snake’s stomach for about a day. It's in my opinion the appropriate size, equal or slightly bigger than the snakes largest girth.
This snake ate a 27 gram fuzzy rat yesterday afternoon(she is 33 days old today)

she is starting her shed cycle, but today there is no bulge in her stomach. if she wasn't going to shed, in 5 days I would feed her about the same size food item.
Young snakes grow fast and as such I feed more frequently
TomChambers