Bum, Jr. threw 62 at age 12. He was the smallest kid on his team. One of the coaches had a radar gun and clocked him. Three or four kids on his team threw harder but none of them currently play the game. He threw maybe 65 at 13, 68 at 14, 72 at 15, 80 at 16, 89 at 17, and tapered off from there to cruising 88-91 tops 92.
Still the shortest pitcher on his team but good enough to play professionally.
Trust me when I say it matters NOT how hard you throw at 11. The hardest throwers then are actually at a disadvantage as their arms are often toast by the time they get to h.s. due to overuse. Bum, Jr. rarely pitched until 13.