When i played Nost i only reached lvl 44 until it got closed. 
There were a SHITTON of people still leveling/freshly dinged 60. 
Lvling in Tanaris or STV, both gank fests, you felt like this server was 1 month old. 
I don't believe that you have problems catching up at all, 
even more so because Nost Pvp launches first. 
There will be a huge wave of fresh 1's that can't wait for fresh release, 
and won't bother to reroll when they grinded 24/7 for weeks and fresh releases.