My while loop goes into it's second iteration before my switch statement executes completely, I'm coding in c++

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

void ReadFile()
{

    string fileName;
    ifstream inFile;

    cout << "Please enter the password for the external file: ";
    getline(cin, fileName);

    inFile.open(fileName);

}//End of ReadFile() function


int main()
{
    vector<string> studentName, studentNumber, studentClass;
    char option;

    while (option != 'g' && option != 'G')
    {

        cout << "\t\t\t" << "Student List Menu\n\n";
        cout << "A.  Reading the Student List from a file\n";
        cout << "B.  Adding Student's Informations into the Student List\n";
        cout << "C.  Displaying the content of the Student List\n";
        cout << "D.  Sorting and Displaying the content of the Student List\n";
        cout << "E.  Writing the Student List to a file\n";
        cout << "F.  Searching for a Student's Information from the Student List\n";
        cout << "G.  Ending the program\n\n";
        cout << "Please enter an option:     ";
        cin >> option;
        cout << endl;

        switch (option)
        {

            case 'A':
            case 'a':
                ReadFile();
                break;

            case 'B':
            case 'b':
                break;

            case 'C':
            case 'c':
                break;

            case 'D':
            case 'd':
                break;

            case 'E':
            case 'e':
                break;

            case 'F':
            case 'f':
                break;

            case 'G':
            case 'g':
                cout << "Thank you for using the program!";
                break;

            default: cout << "Invalid option choice\n\n";

        }

    }

    return 0;
}//End of main function

When I select option 'A', the switch statement calls the ReadFile() function, but when it asks for the "password" (the file name) to be entered, "Student List Menu" is read, which I think means the do-while loop continued to run while executing the ReadFile function, so it read the input until the newline character. What can I do to get it to run the option first, then continue through the do-while loop?