I would feed a large-ish pup (27-29 grams) or a small-ish weanling (30-32 grams) every five days until the snake was up to 300 grams, then move it to a weanling every five days until it hit 500 grams, then a small rat weekly.
If this snake is truly almost three years old and only 230 grams then it's no wonder it will eat whatever you put in front of it!