Hi and welcome to the OB.
Yellowing of the lower or base leaves can just be a sign of natural die back. The lower leaves are the older ones, so should go first. Hopefully that is the case here.
There is usually little need to remove such a leaf by force, it should come away naturally of it's own accord with time. The plant will also absorb back some of the nutrients contained within the dieing leaf.
If there are no other signs of rot or infestation, then this should be the reason for the yellowing and discoloration.
So if the other leaves do not have any spots I wouldn't worry too much. You may be surprised at what these plants can come back from with the right care.
Wishing you all the best with your plant! If I'm wrong in my assumptions I'm sure someone else will pipe in soon enough