(python) I keep getting the error "string index out of range" : so I'm doing some homework and i'm kinda stumped, the assignment is to create a program that makes a email address based on your first and last name and the year you started school, but for some reason I cant get the email to generate I keep getting the "String index out of range" error.

Here is my code:

    # a graphical program that creates a student email adress
    from graphics import *
    import math
    #setting up the window
    win = GraphWin("email",400,400)
    win.setBackground("yellow")
    #setting up the input
    instructions = Text(Point(160,50), "For your email, enter your first and last name,\n and the year you are starting school.")
    instructions.draw(win)
    fstName = Text(Point(100,100),"What is your first name?: ")
    fstName.draw(win)
    fstNameInput = Entry(Point(260,100), 10)
    fstNameInput.draw(win)
    lstName = Text(Point(100,150), "what is your last name?: ")
    lstName.draw(win)
    lstNameInput = Entry(Point(260,150), 15)
    lstNameInput.draw(win)
    year = Text(Point(130,200), "What year are you starting school?: ")
    year.draw(win)
    yearInput = Entry(Point(280,200), 4)
    yearInput.draw(win)
    #Line break
    linBreak = Text(Point(200,289), "=======================================")
    linBreak.draw(win)
    #Output
    email = Text(Point(50,315), "Your email is: ")
    email.draw(win)
    emailOutput = Entry(Point(200,340), 50)
    emailOutput.draw(win)
    #setting up The process
    fst_name = fstNameInput.getText()
    lst_name = lstNameInput.getText()
    YEAR = yearInput.getText()
    #Button
    button = Rectangle(Point(130,250),Point(210,279))
    button.draw(win)
    buttonCenter = button.getCenter()
    buttonText = Text(buttonCenter, "Enter")
    buttonText.draw(win)
    #button function (got help for this on stack overflow)
    def inside(point, rectangle):
        
    
        ll = rectangle.getP1()
        ur = rectangle.getP2()  
    
        return ll.getX() < point.getX() < ur.getX() and ll.getY() < point.getY() < ur.getY()
    
    
    while True:
        click = win.getMouse()
    
        if click is None:
            emailOutput.setText("")
        elif inside(click, button):
            emailOutput.setText(fst_name[0] + lst_name + YEAR + "@student.kathycollege.edu")
            break;

