A program where a user enters his date of birth as an input, and the application gives his age as an output.

ageCalculator.py

import datetime

def get_valid_date(prompt):
    while True:
        try:
            date_str = input(prompt)
            date = datetime.datetime.strptime(date_str, '%Y-%m-%d').date()
            return date
        except ValueError:
            print("Please enter a valid date in the format YYYY-MM-DD.")

def ageCalculator():
    dob = get_valid_date("Enter your date of birth (YYYY-MM-DD): ")
    today = datetime.datetime.now().date()
    age = (today - dob) // datetime.timedelta(days=365)
    return age

print("Your age is:", ageCalculator())