Simplify the following text for a Grade 6 native English-speaking person.
Original: The name Pluto was proposed by Venetia Burney ( 1918 â `` 2009 ) , an eleven-year-old schoolgirl in Oxford , England .
Simplified: The name Pluto was proposed by Venetia Burney ( later Venetia Phair ) . She was an 11-year-old schoolgirl in Oxford , England then .