Here are the world zones in Aion. Know where you can go according to your level. (Source: aiondatabase)
Asmodae
Altgard 10 - 20
Beluslan 41 - 50
Brusthonin 20 - 25
Gelkmaros 50 - 55
Ishalgen 1 - 9
Morheim 19 - 40
Pandaemonium 10 - 50
Elysea
Eltnen 19 - 40
Heiron 20 - 25
Inggison 50 - 55
Poeta 1 - 9
Sanctum 10 - 50
Theobomos 41 - 50
Verteron 10 - 20
The Abyss
Reshanta 25-50