Help me find this anime movie?

So i need help finding the name of this anime movie i once saw. I forgot all characters name but i can somewhat describe the movie (well what happens). Its about this little girl becoming a witch. In the beginning of the movie, its night time, she is at home n the parents r celebrating her becoming a witch. Her mom made her a broom herself. Ummm so yea now the little girl has to go live by herself with her talking black cat. The little girl wears a purple dress btw. So she flies away to another city and lives in the attic of this lady thats let her live with her. So she starts making a living there, doing chores around the city and she starts liking this boy. So anyway thats about all i remember xcept that sometime during the movie she lost her powers (forgot why) and tries to regain them. In the end there was this huge umm thing (A blimp or sumthing i forgot what) that was going to crash into the city and she saves the city w/ her regained powers. Ill tell u if i remember more. thnks