I graduated in early 1967 from RM "A" school. 18 wpm on a straight key was minimum. 30 wpm on a mill was required. My best on a straight key was 24 wpm for 5 minutes, no errors.
At the time your comm command would take you to a FCC office for speed key (Bug) testing, I was at Coronado so no testing was available. Turns out only fleet comms were running high speed CW. My 20 wpm was normal.