Losing short hairs in my crewcut.

Is it normal to lose short hairs if you don’t have MPB

If one gets a crew cut, then when the anagen hairs go into telogen, then you will shed the short hairs as that is the only hair that they have.  Every hair on your head goes into telogen every 2-3 years and recycles. In women, the cycle may be longer than 2-3 years on average, especially younger women.  That means that there is a limit to the length a hair can grow, which is totally dependent on the duration of the anagen component of the hair cycle.