I also wanna add that you can aquire, let's say, 90% of all Kafra Shop Items ingame as well in the way of buying them from other players for zeny (ingame currency).
If you want to play a mage-class however, I would say there are only 3, maybe 4 options:
Mage Cls obviously is the one real Magic Class divided in the Sage and Wizard Class. You could go down and say that Sage is the supporting Mage while Wizard is the attacking Mage, but this is a bit unfair to Sage who also have a hand full or nice damage dealing spells ^^ So, just take it as a "basic", not as a static fact.
The other mage-class would be Ninja, who can specialice on Magic as well. Ninja's are cut down in groth: instead of becoming job 50 first class, 99/50 second class or 99/70 trans second class and 150/50 3rd Class - meaning that they can acquire 167 max Skill Points to use in Skills, Ninjas can only become 99/70, which means 69 Skill points for Skills. BUT there's an update coming for Ninja to allowing them evolve to 150/50 as well. Basically they're still weaker seeing that they have less stat and skill points than "normal" Classes, but their skills are pretty strong and balance this out a bit - unfortunally, we don't know when they arrive here and Ninjas are an expensive class, since they're using elemental orbs for their magic which have to be bought for zeny - which is a knock out for any new player without zeny.
Than there are smaller Magic Dealer Classes.
One of them is actually the Super Novice. It's not a class that's easy to level though, it's tough and not really rewarding except you like playing really tough and weak classes ;D Super Novices are using only first Job skills till they reach 99, and afterwards they have acess to a hand full of 2nd class skills - unfortunally not really strong ones :/
Another one would be Priest as a Magic Dealer Priest, which means Magnus Exorcismus and Adoramus as AB later on. They're reduced to special races on monsters though, precicly only undead and demon monsters. Which means it's a nice class for players who love to play Priest Class and also wanna deal magic damage - but not the target for someone looking for a mage-class.
The last named one, Soul Linker... I wouldn't call it mage-class at all, since the only attack magic you'll use is ONE skill alone. You can change the element of that skill to 7 different elements (which is more than all other classes have from their skills), but it's still the same skill over and over... and like Ninja, the groth is cut for Soul Linker, giving them only the possibility to reach job lv 50 on first class and 99/50 on 2nd class - and there's no update in sight (but hopefully planning) for them to go higher.
So yeah, you should definatly do a Mage.
It's your personal taste that should decide between Sage/Scholar/Sorcerer and Wizard/High Wizard/Warlock.
Warlocks should be easier later on though, but Sage can be nice as well.
No matter what of them you're choosing, you should go with a lot of int and a medium of dex and luk (in my opinion).
Test these stats out till you're 99 and can rebirth, untill then you learn a lot about how growing your char for your "2nd lifetime" where you can place your stats again
Anyway, have fun on iRO ^.^