So I used Matt Garrioch's age spectrum based on Rany Jazayerli's earlier work:
2013-mlb-draft-draft-age-of-high-school-prospects
http://www.baseballprospectus.com/article.php?articleid=15306
http://www.baseballprospectus.com/article.php?articleid=15295
To rank the high school players in 2014 from "very young" to "very old" for their draft classes. Studies have shown that relative draft age has more bearing on position players than on pitchers. Unpolished position players who are old for their class are usually red flags now, however there are a few exceptions. Byron Buxton for one, was old for his class, although he ended up being more polished than people realized.
Anyway, here's the list of the top players based on ages.
Very Old
Cameron Varga, RHP: Aug. 19, 1994
Greg Deichmann, 2B/3B: May 31, 1995
Joseph Gatto, RHP: Jun. 14, 1995
Foster Griffin, LHP: July 27, 1995
Monte Harrison, OF: Aug. 10, 1995
Michael Chavis, 3B: Aug. 11, 1995
Jon Littell, OF: Aug. 16, 1995
Sean Reid-Foley, RHP: Aug. 30, 1995
Jacob Gatewood, 3B: Sept. 25, 1995
Jack Flaherty, OF/RHP: Oct. 15, 1995
Michael Gettys, OF: Oct. 22, 1995
Nick Gordon, SS: Oct. 24, 1995
Cobi Johnson, RHP: Nov. 6, 1995
Josh Morgan, SS: Nov. 16, 1995
Old
Forest Wall, 2B/OF: Nov. 20, 1995
Keith Weisenberg, RHP: Dec. 6, 1995
Tyler Kolek, RHP: Dec. 15, 1995
Alex Jackson, C/OF: Dec. 25, 1995
Dylan Cease, RHP: Dec. 28, 1995
Mac Marshall, LHP: Dec. 28, 1995
Derek Hill, OF: Dec. 30, 1995
Luis Ortiz, RHP: Dec. 30, 1995
Jakson Reetz, C/OF: Jan. 3, 1996
Keaton McKinney, RHP: Jan. 3, 1996
Jacob Nix, OF: Jan. 9, 1996
Alexis Pantojas, SS: Jan. 18, 1996
Jeren Kendall, OF: Feb. 4, 1996
Justin Smith, OF: Feb. 29, 1996
Average
Grant Holmes, RHP: March 22, 1996
Scott Blewet, RHP: Apr. 10, 1996
Gareth Morgan, OF: Apr. 12, 1996
Bryce Montes de Oca, RHP: Apr. 25 1996
Michael Kopech, RHP: Apr. 30, 1996
Young
Devon Fisher, C: May. 1, 1996
Justus Sheffield, LHP: May 13, 1996
Alex Verdugo, LHP/OF: May 15, 1996
Kodi Medeiros, LHP: May 25, 1996
Braxton Davidson, 1B/OF: June 18, 1996
Touki Toussaint, RHP: June 20, 1996
Very Young
Marcus Wilson, OF: Aug. 15, 1996
Brady Aiken, LHP: Aug. 16, 1996
Chase Vallot, C: Aug. 21, 1996
Ti'Quan Forbes, SS: Aug. 26, 1996
Jacob Bukauskas, RHP: Oct 11, 1996