Simplify the following text for a Grade 7 native English-speaking person.
Original: In the United Kingdom , a person generally starts secondary school at age 11 and finish at either 16 or 18 depending on whether the secondary school has a sixth form offering post 16 education .
Simplified: In England and Wales secondary school is for children from the ages of 11 to 16 or 18 or in some cases 19 .