Cincinnati Reds pitcher Joe Nuxhall, who made his debut at the age of 15 in 1944, was the youngest ever.
Nolan Ryan
50 50 % chance
Christian Haupt was the youngest person to throw the ceremonial first pitch at an MLB game. He was just three years old when he threw the first pitch at the Los Angeles Dodgers game on 9/4/2012.
Ray Chapman of the Cleveland Indians in 1920.
If you mean the youngest pitcher, it should be Joe Nuxall for Cincinnati Reds, he first pitch in major on June 10th, 1944, at age 15 years, 314 days. He didn't pitch again in the majors until 1952
In general, add aboout 20 mph because you are calculating the different pitching lengths. Little league pitchers throw from 45 feet, major leaguers throw from 60.5 feet. For example, a little league pitcher throwing a 70 mph pitch is equivalent to a major league player throwing about a 90 mph pitch.
On Aug. 16, 1920, Cleveland Indians shortstop Ray Chapman - the only Major League player to be killed by a pitch - was struck in the temple by Yankee pitcher Carl Mays.
Nolan Ryan has been noted as the first player to pitch over 100mph, but the real answer is unknown, because the earlier pitchers didn't have radar guns.
knuckleball
46- knuckle
56 mph