"Why Not" Is A Song Recorded By American Actress And Singer Hilary Duff. It Was Written By Charlie Midnight With Matthew Gerrard Who Also Produced The Song. It Was Released On April 15 2003 By Walt Disney Records As The First Single From The Lizzie McGuire Movie Soundtrack. The Version Of The Song On Duff's 2003 Album Metamorphosis Features Different Lyrics In The First Verse.