Yes, it is possible and most likely the egg was not fertile. Not sure if the egg wasn't fertile due to this being their first round, though.
When there is a 3 day difference in age, you do need to keep your eye out on the younger one. I usually remove the older baby each time they feed the babies, and then return the older baby to be fed. Do this until the baby has grown and strong enough to compete with the older baby. You can avoid this issue by removing the first egg when it is layed and return it to the hen when the second is laid, and then incubation will be the same time. Usually the older more experienced hens will lay near the first egg, but not incubate it until the second one is layed.