[andrewas]

The 3E system is something like 1d20 + your attack bonus must beat (or equal?) your targets AC.

And mage armour isnt the best choice for a level 1 mage - all it will do is make you slightly tougher in melee, whereas the place for a mage is in the back ranks dealing ranged damage. With your attack bonus and HP, you dont want to be anywhere near anything more dangerous that a rat.

Not that a level 1 mage can make much use of Magic Missile, but that 1d4+1 damage can be useful at the right time, especialy for spellcaster disruption you dont want to risk on a bowmans accuracy.