PvP mounts (black ones) are available for purchase on rank 11 (Commander/Lieutenant General) or higher.
Minimal character level requirement for rank 11 is lvl 53.
PvP mount require only Apprentice rank (75 skill points) of Riding skill and character level of 40.
It seems like nothing prevents you from riding +100% spd mount before lvl 60.
Is it really possible?
Have anyone done this?