Return of Reckoning

playing a dark elf lvl 17 and can not find any where i can by my new mount and able to help

Go to the stables (north-west) in the city for the mount vendors. Apparently there is a slightly cheaper option somewhere (one of the PvE chapter camps?) but I always forget where...

After lvl 16 you can enter the "main" RvR campaign and will get bolstered up to give you a chance against max lvl players in pvp (scenarios and open RvR zones)
the lvl 16 50% mount can be purcashed in the capitals for 10g i think it is.

For Order players that would be down south in Altdorf at the Mount vendor.
For Destro players it will be North west up a floating island close to the pyramid thingy. (showing as the Yellow area on the city map)

Thank you