Niall Horan, Zayn Malik and Liam James Payne are all 19years. Harold Edwards Style is 18 years while Louis Tomlinson is 21 years. One Direction signed to Simon Cowell's record label Syco Records. This was after being formed and placed third in the seventh series of The X Factor. Read more on http://en.wikipedia.org/wiki/One_Direction#Niall_Horan.
Louis Tomlinson:December 24,1991 (21) he's the oldest Zayn Malik:January 12,1993 (20) 2nd oldest Liam Payne: August 29,1993 (19) middle Niall Horan: September 13,1193 (19) close to youngest Harry Styles:February 1,1194 (18) youngest