Practicing using a "flag": please point in right direction

[magsloo]

I'm currently going through the Python Crash Course and I'm on Chapter 7. I'm attempting to use an active variable to control how long the loop runs.

prompt = "\nWhat is your age?"
prompt += "\n(Enter 'quit' when you are finished.)" 

active = True 
while active: 
    age = input(prompt) 
    
    if age == 'quit': 
        active = False 
    age = int(age)
    if age < 3:
        print("\nYour ticket is free!") 
    elif age < 12: 
        print("\nYour ticket is 10$!") 
    else:
        print("\nYour ticket is 15$!") 
        

The above works until I enter quit.

Error:
Traceback (most recent call last):
  File "parrot.py", line 10, in <module>
    age = int(age)
ValueError: invalid literal for int() with base 10: 'quit'

I know that this is because I change age data type to an integer data type so I can use the comparison operators However, quit is not an int. I feel like maybe this is a matter of placement? I've tried different placements (before the if age == 'quit') but it's still not working. Could someone please point me in the right direction? Thank you!