well if you want singletarget dps go warden its stronger there but if you want aoe dps go mage cuz thats his strong point
but cuz you are new i think you want to do pve so here a little list on advantages:
Mage:
- Better buffs (Seal,Aop)
- Better AOE Damage
- Emergency Group Teleport
Warden:
- Better Singeltarget Dps
- even as a Dps you can easily be a fullheal at the same time
- more defense than the mage
that sums the advantaged pretty much up but 1 last point would probably be if you still have to lvl (and well i guess you do
) choose warden cuz its way better to lvl cuz your pet is a tank for you and you can easily play alone till max lvl (well ofc a mage can too but its a bit tricky to kill some bosses as a mage)