I think you should wait at least a week before feeding a new snake. But you should also realize that some snakes have unique feeding habits and you'll have to learn what your snake's are. My female yellowbelly is so dense when it comes to feeding. A f/t rat could be sitting right on her or in front of her face and she won't be able to find it. She'll go crazy because she can smell it, but she can't find it. I usually have to pick it up and dangle it in front of her face 2-3 times before she'll finally strike. My albino male is a great eater and never misses a first strike and my rainbow boa is super shy. She will not eat in front of anyone and I have to leave the pinky in front of her hide. It's always gone by morning.

You'll come to find out your snake's feeding habits with time. Sometimes it takes a bit of experimenting Good luck.