Just looking at the timing of my USArmy (Infantry, Big Red 1) son-in-law.
He may be above average?
Recruit to E-5 in 4 years, squad commander in his 2nd deploy to Ghanny. Now a DI. Interestingly enough...he still has his squad command, too.
Corps ain’t the Army, TBTG. Promotion to Corporal is a big deal. I’m sure he was a L/Cpl when he finished school, welcome to the fleet, we’re deploying.