If you are wondering how old is Arya in season 8 of Game of Thrones, Arya is 18 years old. The character was 11 in the first season of the show when it first went to air, there has been 8 seasons which makes Arya 18 years old now. The show has moved forward about one year in time for each season of the show. In the books though the character was a little younger, she was 9 in the first book. But in the show the character was made a little older.
If you are wondering how old is Maisie Williams? She was born in 1997, which makes her about 22 this year.