Calculating your age via datetime library. Soon to be updated to include months, days.

What is My Age?.py

from datetime import datetime

# what is my age?
while True:
    try:
        birth_year = int(input("Enter your birth year: "))
        current_year = datetime.now().year
        age = current_year - birth_year

        #if birth_year <= 0 or birth_year < 1910 or birth_year >= current_year:
        if not 1910 < birth_year < current_year: 
            print("Enter a valid birth year.")
        else:
            print(f"You're {age} years old.")
            break
    except ValueError:
        print("Enter a valid year.")