If the mount is a reward for season 3 and assuming season 4 rewards the same item. A possible 260 players per data center would have this reward. It actually not that hard to get into the top 100 solo or top 30 light party, just keep trying and try to improve as much as possible and even if you dont get it for season 3 you still have season 4 with probably less competition to get it except this time you have more experience.