If anything I found the game really easy (playing a Mage as well). But a mage cannot become reliant on magic alone until they're a decent level - I think I was in my low teens before I had enough mana and damage to kill just with magic.
Until then, use a bow, you'll find it much more effective than your mage spells at low levels. But don't put any points into bow skills, bows become much less useful when you level gets high.
And by the time you reach level 40+, you'll be killing pretty much any opponent with a single fireball, so you've got something to look forward to
