I have the following Python code snippet.

class LoggedAgeAccess:

    def __get__(self, obj, objtype=None):
        value = obj._age
        return value

    def __set__(self, obj, value):
        obj._age = value

class Person:

    age = LoggedAgeAccess()             # Descriptor instance

    def __init__(self, name, age):
        self.name = name                # Regular instance attribute
        self.age = age                  # Calls __set__()

    def birthday(self):
        self.age += 1                   # Calls both __get__() and __set__()

x = Person("ABC", 27)

In the constructor, the second assignment statement self.age = age triggers the __set__() method of the LoggedAgeAccess descriptor.
This is really confusing.

When the Person object is created, I am passing name and age values. Inside the constructor, I refer the passed value and create a instance specific variable self.age
whose value is assigned with the passed value (27). How this assignment statement refers the class level age variable and triggers a call to __set__()?