Forced Server switch.
You choose your server in the beggining, before creating a character. Since you choose Yaks Bend you will stay Yaks Bend for every character, even if you delete them.
You can always transfer
There is a 7 day waiting period between transfers (and the game considers choosing a server at start the same as a transfer). The waiting period was put in place because of people switching servers frequently and causing problems with WvW (World versus World).
The game has Megaservers though. This means that the players in PvE and PvE are pooled together for the NA and EU servers. The only place where servers make a difference is in WvW. If you aren’t going to play there or don’t care what WvW server you are on then you can stay on Yaks Bend and play with your friends and guild mates with no problems at all.
Transferring: http://wiki.guildwars2.com/wiki/World#Transferring
Megaservers: https://www.guildwars2.com/en/news/introducing-the-megaserver-system/
ANet may give it to you.