Most of mine have been rescue pigs, a lot of those we had no idea how old they were when they came here so ageing them was all guesswork.
One of my first pigs was really ill at one point, and the vet said he probably won't make it until Christmas, take him home and make him comfortable. Well, he was one of those who surprised us in a good way and was not only there for Christmas, but the following Christmas also.
On the other hand I have lost pigs too young. It hurts however it happens.
It's normal to dread your pet's death, but your piggy won't be thinking about it at all. All he cares about is if his life is good right now.