Class vs. Instance python3 code example

Example: Class vs. Instance python3

class Person:
    def __init__(self,initialAge):
        # Add some more code to run some checks on initialAge
        if initialAge < 0:
            self.age = 0
            print("Age is not valid, setting age to 0.")
        else:
            self.age = initialAge
    def amIOld(self):
        # Do some computations in here and print out the correct statement to the console
        if self.age < 13:
            print("You are young.")
        elif self.age>=13 and self.age <18:
            print("You are a teenager.")
        else:
            print("You are old.")
    def yearPasses(self):
        # Increment the age of the person in here
        self.age += 1