I was wondering if i am strong enough to beat the cursed abbey, the troll passage or the orc chief...?
As a general rule, I'd say : the more you are away from Aleroth, the stronger the enemies get.
One aproach could be to emphasize non-fighting (or "few-fighting" quests first to get more experience points, until you believe you might be strong enough.
Unfortunately the "strength-factor" <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" /> is hard to determine - the weapon and spells - effectively used - can be of great help. Especially frost.