in his teens
She was nine years old when she got the part.
She started at the age of nine years.
She was 11 years old.
She was 11, Her first film was Harry Potter and the Philosopher's Stone :)
She's over twenty years old now, so presumably.
When they started fiming the first film they were 10
Emma Watson was approximently 21 years old in deathly hallows part 1 since she was 10 when she started... basically a decade later!!
11 and Her acting Debut was Harry Potter and the Philosopher Stone