Acutally, the challenge level of the game is generally correct proportionate to the levels involved. At 16 your characters are already much higher level than most of the famous protagninists in the forgotten realms, and just think of the crazy stuff they accomplish
. The learning curve is quick, so I'd recommend you stay with it for a bit and not cheat before throwing it out. The first time I went through Nalias keep on easy I could barely kill any of the trolls and thought it was impossible. Two weeks later I was able to kill all the trolls and all the golems(including the iron golem) on the highest difficulty level with an incomplete party without cheating. You may want to try changing the difficulty slider also, it really does help dramatically.