I am not intending to give too much information or anything too specific here, merely gather the various tidbits around the forum in one place and supply some basic info about what you are getting into. Also, wizzies/admins do step in should I divulge too much. I rarely have good sense about these sort of things
Mages have a coded requirement for joining that cannot be bypassed with leadership sayso's. That is, a mage requires very good mentals. INT specifically. You might be looking into months of(or even more if you are not obsessive)RL time during which you preferably do quests with stat prefs set on INT and improve INT-skills.
A mage needs his/her mentals be higher than physical stats as well. This does not mean there cannot be buff mages. If you have ludicrously good mentals you can have nice physical stats as well but godlike fighter physicals are realistically out of reach.
You do not need to be a mage to know magic. Learning some might be a good idea before you start pestering a mage master.
Mages have limited membership slots, in a way. You need to apprentice under a master and those slots when filled, can remain occupied for quite a while.
Geas magic is not like AD&D magic where mages hide behind inpenetrable barriers and summoned monsters while flinging endless volleys of magic missiles and fireballs at your foes. Combat magic surely exists and can be powerful but even when you are at the point where you can cast something meaningfully harmful reliably, you will not even be blasting yourself through a goblin camp. Even less so if your character has puny physical stats and lacking combat skills. A mage getting hit is easily toast, or at best your spells become interrupted. Actual combat skills help here.