The stub of getFirst() should look like this:
   Item List::getFirst() const {
The steps it should take are:
  1. If mySize is not positive OR myFirst is NULL:
    throw an underflow_error exception.
  2. Return the value of myItem in the Node whose address is in myFirst.
You will need to #include <stdexcept> in order for underflow_error to be declared.