Nobody is "executing 14 year olds."
Simmons, the case in point, was eight months short of 18 when he hogtied a woman, duct-taped her mouth closed, kidnapped her, and shoved her off a train trestle into a river.
He was eighteen when sentenced, and like most other "death row" inmates is living a long life running through the endless process of appeals. He is now 28.
Get a grip.