What do you mean "in the roof"? Do you mean in the attic?
Age shouldn't matter unless it is outside. Length, gauge and whether it is High Speed or Standard Speed matters.
I suspect in this case, the answer is going to be to try it. If it doesn't work it will be obvious. If it doesn't work, then you can worry about how you are going to replace it. 3D is less bandwidth than 1080p/60, so if you can do 1080p/60 right now, you should be OK for 3D.