hello, and welcome to world of warcraft, also know as forfit your life.
there not much comfuse about the diffrence between US, Oceanic and Latin America,

US simply mean its the group of server meant for US region, i think the US slipt to 4 or 5 categories: something like East coast(NY, NJ), central American, West Coast(LA, CA)

Oceanic are for time zone like for Aus, New Zeland, Hawaii, and asian

and Latin might be for the south american, for people chat none english, spanish or portogis

main diffrence is for the time zone we play and the distance from the server.

most asian and Aus play in oceanic server. simple everybody said and think that its suitable for our timezone.
U don't want to play in a US NewYork time zone where everybody asleep, and you just started login, do you?

you want in pvp or pve server? that important too,
there are some player will gank and camp you all day,
simply because of pass trama he/she suffer or because he is level 85 and lost his raid spot, take out the anger on you.

since you just started,(level30~40?)
i suggest you just re-roll, save some money

also i notice both of you are in diffrent faction,
alliance and horde...