Bottle feeding

Hey mommas I have a three month old princess and she was born 5 weeks early but she sure don’t act like a preemie lol. Well I’m worried about her feedings. We usually feed every three hours and she’ll only eat 3 ounces. Today we took a very well needed long nap and she went five hours and we ate as soon as we woke up and she’s just about drank twice her normal feeding. Everytime I bring up to family that I’m thinking on waiting alil longer to feed they make me feel as if that’s a horrible idea. I want her to eat more and I’m not sure if I should keep feeding every three hours or if I should feed every four to five hours or even on demand what do y’all think ?